Aha! Do you know what that factoid shows, though? Just the opposite of what you are citing it to prove! To wit:
1. Some Democrats thought for themselves and broke ranks with the majority of their party to vote against impeachment (or abstain).
2. Republicans, to a man, voted against impeachment in lock-step. (The sole exception, Justin Amash, had already left the GOP.)
So who's more open-minded about impeachment: Reps or Dems?