I think the motivation behind this is to make you upvote questions more in general, just like the Electorate badgeElectorate badge encourages upvoting of questions. Giving you a counter that tells you "I've already upvoted enough questions, so now I can upvote answers" would be beside the point here.
However, if you really wanna keep track, you could go to your profile and check the "votes" tab ⇒ upvotes (not taking downvotes into consideration here). This doesn't directly tell you which ones were on questions and which ones on answers, but if you mouseover the link and check the target URL, you can tell:
That's an answer:
That's a question:
But you'll have to count manually.