On any given day we get about 1% downvotes compared to upvotes (for instance, 7 downvotes for 220 upvotes) across the site. This strikes me as a very low number of downvotes, but I don't have any data to compare it with.
While I can't share it with you, I can tell you that our moderator analytics tools indicate that our downvote to upvote ratio is very, very low. As aforementioned, my estimates put downvotes per day at roughly 1% of upvotes per day.
Regardless of how it compares to other Stack Exchange websites: is downvoting being used "correctly" on UX? How do we want downvotes to measure up to upvotes? Are we getting enough or could we use more?
Remember, downvoting is a great way to help organise content and indicate to people which questions could use some work, especially when you don't have time to help improve things otherwise.