Since becoming an adult, how many Americans have ever had a sexual experience with someone of the same sex? And how has this number changed over time? According to a recent study published in the Archives of Sexual Behavior, 8-9% of American adults today have had a same-sex experience—a figure that has doubled since the late 1980s. Check out the infographic below for a closer look at the numbers and how they have changed over time.

In this infographic, you’ll also see that this rise in same-sex behavior is primarily a function of more Americans today being behaviorally bisexual. In other words, we’re not necessarily seeing a lot more in the way of exclusive same-sex behavior, but rather we’re mostly seeing an increase in people who report sexual activity with both men and women.

So what’s behind this change in Americans’ sexual behavior patterns? We can’t say for sure, but there are several possibilities. One is simply that more Americans are comfortable reporting same-sex behavior today than they were in the past due to the greater social acceptability of homosexuality and bisexuality. In other words, maybe there hasn’t been that much of a change in behavior and what we’re seeing is mostly a change in reporting.

Alternatively, it might be that more Americans are actually engaging in same-sex behavior. This could also be potentially attributable to increasing acceptance of sexual diversity. For example, in the past, at least some people with same-sex attractions may have never acted on them due to fear of social and (in some cases) legal consequences; however, as the likelihood of experiencing such negative consequences has decreased, those who might have otherwise been too afraid to act on their desires might now be more inclined to do so.

Regardless of what’s behind this change in numbers, it’s important to point out that this study focused on sexual behavior—not sexual identity. Sexual behavior and identity are not the same thing; however, I should note that there is at least some data to suggest that paralleling this increase in reporting of same-sex behavior is an increase in LGB identification.