You have to read the text for details: The most substantial cultural and political divides are between white Christians and Christians of color. More than four in ten Americans (44%) identify as white Christian, including white evangelical Protestants (14%), white mainline (non-evangelical) Protestants (16%), and white Catholics (12%), as well as small percentages who identify as Latter-day Saint (Mormon), Jehovah’s Witness, and Orthodox Christian[2]. Christians of color include Hispanic Catholics (8%), Black Protestants (7%), Hispanic Protestants (4%), other Protestants of color (4%), and other Catholics of color (2%)[3]. The rest of religiously affiliated Americans belong to non-Christian groups, including 1% who are Jewish, 1% Muslim, 1% Buddhist, 0.5% Hindu, and 1% who identify with other religions. Religiously unaffiliated Americans comprise those who do not claim any particular religious affiliation (17%) and those who identify as atheist (3%) or agnostic (3%).
17 + 3 + 3 = 23% in the pie chart under "Unaffiliated"