UCLA Fall 2018 Transfer: History Major

Interestingly, History used to be an impacted major at UCLA for quite some time, its only recently that it has become non-impacted with a high acceptance rate. (For example in 2011, History was listed as an impacted major and it had a 41% acceptance rate, whereas in 2017 it had a roughly 64% acceptance rate). Does anyone know why this happened? Maybe the history department increased its class capacity allowing more students to be accepted? Or is it maybe because the History major has decreased in popularity/rankings? (I mean I’m not complaining because this actually boosts my and current applicants chances at getting in, but im curious as to why formerly impacted majors can become nonimpacted in a relatively short amount of time)