What is the origin of catgirls, and when exactly did they become popular in the west?

Was it the anime boom that started around the early 2000s? I have no recollection of even seeing catgirls in any anime that I used to watch back then, unless it was anime that I had to find out on the internet and watch through fansubs. <br><br>I have been exhausted with the sheer amount of sexualization of catgirls that I think I would have remembered seeing them all over anime around that time.