Lexical drift

[Batcathat]

Another usage I've heard from my daughter - instead of "by accident", she describes things as happening "on accident" - presumably in contrast to "on purpose". Is that just her, or is it more widespread?

I've heard/seen people using it (though I live in a non-English speaking country so my exposure is mostly through the internet and pop culture), but it seems less popular than "by accident". I did a quick and thoroughly unscientific experiment by searching for either phrase on Google and the result was 10 000 000 results for "on accident" and 57 000 000 results for "by accident", for whatever it's worth.

EDIT: I just noticed that if I do the search multiple times, the amount of hits changes for some reason (maybe someone more knowledgeable about the mysteries of search engines can explain why?) but the numbers seem to stay roughly in the same ball park.