A recent study by the Williams Institute at UCLA has estimated the U.S. adult transgender population at 0.6%, or 1.4 million people. This estimation is twice that of a 2011 study by Gary G. Gates, which used data from 2003, 2007, and 2009. According to the recent study, the newer information is more detailed and uses larger sample sizes.
The Williams Institute study used answers from the 2014 Behavioral Risk Factor Surveillance System and data from the American Community Survey by the U.S. census bureau to estimate transgender populations for all 50 states. Percentages ranged from 0.3% in North Dakota, to 0.78% in Hawaii.
The study also found trends in trans identity among age groups, noting that 18-24 year olds had the highest percentage at 0.7%, while older groups of adults had lower percentages.