Obtaining precise numbers on the demographics of sexual orientation is difficult for a variety of reasons, including the nature of the research questions. Most of the studies on sexual orientation rely on self-reported data, which may pose challenges to researchers because of the subject matter's sensitivity. The studies tend to pose two sets of questions. One set examines self-report data of same-sex sexual experiences and attractions, while the other set examines self-report data of personal identification as homosexual or bisexual. Overall, fewer research subjects identify as homosexual or bisexual than report having had sexual experiences or attraction to a person of the same sex. Survey type, questions and survey setting may affect the respondents' answers. This article lists demographic studies of sexual orientation from different countries. Tables comparing several cities' population numbers are also included below. General findings A 2016 literature review stated that "in all cultures the vast majority of individuals are sexually predisposed exclusively to the other sex (i.e., heterosexual) and that only a minority of individuals are sexually predisposed (whether exclusively or non-exclusively) to the same sex." They state that there is no persuasive evidence that the demographics of sexual orientation have varied much across time or place. Bisexuality comes in varying degrees of relative attraction to the same or opposite sex. Men are more likely to be exclusively homosexual than to be equally attracted to both sexes, while the opposite is true for women. Surveys in Western cultures find, on average, that about 93% of men and 87% of women identify as completely heterosexual, 4% of men and 10% of women as mostly heterosexual, 0.5% of men and 1% of women as evenly bisexual, 0.5% of men and 0.5% of women as mostly homosexual, and 2% of men and 0.5% of women as completely homosexual. An analysis of 67 studies found that the lifetime prevalence of sex between men (regardless of orientation) was 3–5% for East Asia, 6–12% for South and South East Asia, 6–15% for Eastern Europe, and 6–20% for Latin America. The International HIV/AIDS Alliance estimates a worldwide prevalence of men who have sex with men between 3 and 16 percent. A small number of people do not feel sexual attraction and identify as asexual, which can be considered a sexual orientation in itself or a lack thereof. By country Worldwide 2021 In 2021, Ipsos interviewed people in 27 countries spanning all continents on