The United States has the world's largest Christian population. In a 2014 survey, 70.6% of adults in the United States identified themselves as Christians; Protestants accounted for 46.5%, while Catholics, at 20.8%, formed the largest single Christian denomination. In 2014, 5.9% of the U.S. adult population claimed a non-Christian religion. These include Judaism (1.9%), Islam (0.9%), Hinduism (0.7%), and Buddhism (0.7%). The survey also reported that 22.8% of Americans described themselves as agnostic, atheist or simply having no religion—up from 8.2% in 1990. Membership in a house of worship fell from 70% in 1999 to 47% in 2020, much of the decline related to the number of Americans expressing no religious preference. However, membership also fell among those who identified with a specific religious group.