That's according to the latest annual report from the U.S. State Department, which rates 188 countries on their efforts to stamp out trafficking in persons.
But still, some of the 2015 rankings are controversial with rights groups questioning whether politics has trumped that ambition.
Malaysia, for example, has been upgraded, while Thailand remains on the list of worst-performing countries. Both are part of of people-smuggling route for Rohingya Muslims fleeing persecution in Myanmar.
Mass graves holding the bodies of dozens of migrants were discovered in Malaysia earlier this year, after the cutoff for this year's TIP Report.
The report raises Malaysia to the Tier 2 Watch List from bottom-ranked Tier 3, where it fell last year, after two consecutive years of failing to do enough to address the issue.
The fall was an automatic downgrade, in compliance with rules introduced by the State Department in 2013 that dictate a country has to move up or down after two years on the Tier 2 Watch List.
Thailand was also demoted for the same reason, but this year remains on Tier 3, an apparent discrepancy for activists who were pushing for both countries to remain in Tier 3.
State of human trafficking
The U.S. State Department puts countries that do the most to fight human trafficking in Tier 1, and the least in Tier 3. Tier 2 includes a Watch List for countries in danger of dropping to Tier 3.
This year, 18 countries were upgraded and another 18 were downgraded. Those downgraded from the Tier 2 Watch List to Tier 3 included Belarus, Belize, Burundi, Comoros, the Marshall Islands and South Sudan.
Penalties for countries demoted to Tier 3 are at the discretion of the U.S. President, but could include restrictions on non-humanitarian assistance and funding.
Alongside Malaysia, upgrades from Tier 3 to the Watch List included Cuba, the Democratic Republic of Congo, Papua New Guinea, and Uzbekistan.
Kerry said: "It is a battle against money. It is a battle against evil. It is remarkable that in 2015 we face a modern-day version of slavery."
Mass migrant graves
Two months ago, it emerged that deep in the jungle along Malaysia's border with Thailand were abandoned makeshift prisons once thought to hold migrants held for ransom by human traffickers.
Alongside wooden cages were mass graves believed to hold the bodies of Bangladeshi migrants and Rohingya Muslims fleeing Myanmar, also known as Burma.
Similar macabre scenes had been earlier uncovered in jungle camps in Thailand,
after a series of raids by Thai police. On Friday, Thailand announced it had charged 72 people with crimes of human trafficking and was looking for another 32 suspects still at large.
In May, Malaysia hosted talks
with delegates from Thailand and Indonesia about how to address the growing crisis of migrants trapped on trafficking boats off the coast. Malaysia and Indonesia agreed to take the migrants in, provided they were given help to resettle them with one year.
However, the raids, arrests and talks came after the March 2015 cut-off for consideration in this year's report, which will raise questions as to why Malaysia was upgraded, yet Thailand remains on Tier 3.
Rights activists point out that Malaysia is one of the countries in negotiations with the U.S. as part of the Trans Pacific Partnership (TPP) agreement. An amendment to the Trade Promotion Authority Act
states a fast-track deal can't be done with a country that's on the Tier 3 list.
Phil Robertson, Asia division deputy director for Human Rights Watch, said: "Malaysia's record on stopping trafficking in persons over the past year is far from sufficient to justify this upgrade from Washington. Migrants are being trafficked and abused with impunity, Rohingya victims' bodies are being pulled from shallow graves at the border and convictions are down year on year. How can the State Department call this progress?"
He added: "The discussion on Malaysia is... a triumph of diplomatic writing trumpeting process rather than impact. This upgrade is more about the TPP and U.S. trade politics than anything Malaysia did to combat human trafficking over the past year. Sadly, this action does significant damage to the credibility of a report that is a critical part of global efforts to combat slavery."
Before the report's release, the Alliance to End Slavery and Trafficking (ATEST) said any move to upgrade Malaysia would be "purely political and incredibly detrimental to combating human trafficking in that country."
Meanwhile, the Thai Ministry of Foreign Affairs released a statement saying its ranking "does not accurately reflect the significant efforts" made over the year. It said Thailand "translated its genuine political will to combat human trafficking into practical policies, effective implementation, and concrete results" calling the issue a national priority.
It added Thailand had cracked down on trafficking gangs and corrupt officials, and was tackling slavery in the fisheries industry.
Other notable changes on this year's list:
promotion from Tier 3 to the Tier 2 Watch List comes just a week after restoration of the country's diplomatic ties
with the U.S., which were frozen in 1961.
After three consecutive years on the Tier 2 Watch List, Kenya
where Barack Obama
has just made his first trip since becoming U.S. President --
made it back on the Tier 2 list. It follows last year's recommendation to increase the number of prosecutions, raids and inspections of potential trafficking hubs.
Saudi Arabia also made it off the bottom tier after making progress in prosecuting offenders and protecting trafficking victims. However, the 2015 report said that it was still not "proactively" investigating and prosecuting employers for withholding workers' passports and pay.
Of the downgrades, Belarus earned an automatic demotion to Tier 3 after two years on the Watch List, as did Comoros, an island off the coast of Eastern Africa, where the report says children are particularly at risk of forced labor.
Child trafficking is also considered to be a huge problem in Ghana
, which dropped to the Watch List from Tier 2. The country is set to receive $5 million in U.S. aid to combat the problem after the signing last month of the Child Protection Compact Partnership.
The money will be used to pursue offenders, rehabilitate victims and educate the public.
Egypt also dropped to the Watch List, following its poor record of addressing the sexual exploitation of women and children. This year's report said that while the country had set up a national anti-trafficking hotline, its efforts to address the problem focused on Egyptian nationals, not foreign trafficking victims.
Considered a corridor for men, women and children trafficked to Western Europe, Slovenia was downgraded from Tier 1 to Tier 2. The report said that while the country was trying to train law enforcement officers, prosecutions were at a five-year low and there had been no convictions at all during the year.