For a healthy normal average human, it's common that their jaws are almost on the same vertical line as their foreheads. The jaws in this picture are more similar to jaws in real life:
However, I have noticed a recent change in art style in the anime industry, that is, characters' jaws tend to be very forward, as is drawn in the following pictures:
A very good witness lies in the anime Detective Conan, whose early art style years ago didn't draw its characters' jaws so forward as today.
Why do anime characters nowadays tend to have very forward jaws? What causes this trend?