Washington (CNN) -- Drivers and passengers in the 21st century have heeded the call to "buckle up."
That famous admonition became a widely used catchphrase in the second half of the 1900s when seat belts became mandatory in cars. Then came the national campaign to "Click it or Ticket." Now the overwhelming majority of people are using the safety straps in record numbers.
Seat belt use in 2012 reached a high of 86%, up 2 percentage points from a year earlier. That's encouraging news for the projected 39.1 million people who will be traveling this Thanksgiving holiday on the nation's highways.
According to the National Highway Traffic Safety Administration's annual survey, seat belt use has steadily increased since 1994, coinciding with a decline in the percentage of unrestrained daytime passenger vehicle fatalities.
Some of the most significant improvements occurred in the South, where seat belt use rose from 80% in 2011 to 85% this year. The West has the highest percentage of users with 94%.
Seat belt use continues to be higher in states that have primary belt laws that allow law enforcement officers to issue citations to motorists, the safety agency said.
It points out that 32 states and the District of Columbia have passed primary laws requiring seat belt use. Another 17 states have weaker "secondary" laws, under which motorists can be cited for seat belt use only if they have been pulled over for another violation.
"New Hampshire is the only state that has not enacted either a primary or secondary seat belt law, though the state's primary child passenger safety law applies to all drivers and passengers under the age of 18," according to the safety agency.
"When it comes to driving safely, one of the most effective ways to protect yourself and your family is to use a seat belt," Transportation Secretary Ray LaHood said in a statement released along with the annual report. "This Thanksgiving holiday, we're urging everyone on our roadways to buckle up -- every trip, every time."
As part of the survey's complex statistical methodology, observers look for seat belt use on randomly selected roads. Observations are made either while standing at the roadside or, in the case of expressways, while riding in a vehicle in traffic.