What ecchi anime are popular among people in 30s or older?

While I am not in 30s, it has always been interesting to see how different taste are in different age group. I honestly have no clue, I can guess what ecchi anime are popular among 20s or 19 and 18.

Most of my favorite ecchi anime are from 2015 like prison school and Monster Musume and these were in my teenage years.