The Delta variant now accounts for an estimated 93.4% of coronavirus circulating in the United States, according to figures published by the US Centers for Disease Control and Prevention.
This includes several sub-lineages of Delta, all of which are classified as variants of concern. Together, they made up about 93.4% of cases during the last two weeks of July.
This number is even higher in certain parts of the country, including the region that includes Iowa, Kansas, Missouri and Nebraska, where Delta accounts for more than 98% of circulating virus.
These figures have shown a rapid increase over the past two months. In the two weeks ending May 22, for example, Delta's prevalence was estimated around 3%.
At that same time in May, another variant first identified in the UK – Alpha, or B.1.1.7 – was the dominant one in the US, causing 69% of cases. Now, CDC's most recent estimates put that variant at just under 3%.