Good question. No polls were taken in '18 and '19. These polls are notoriously inaccurate but interesting. In this case the data was gathered by telephone and that creates an artifact since who wants to give the details of their sex life to some stranger on the phone? It seems certain that the LGBTQ numbers are above the reported seven percent, don't you think? If I had to guess, I would say that the bump was the result of generally more openness about sexual matters. The best way to gather this sort of information would be by blind poll so no one knows your name or, especially, your telephone number.