There is often some discussion on whether or not we should just bet dogs. Here are some interesting stats where you can see how underdogs performed vs. favourites, per event. For example, you can see what your earnings would have been betting $10 on every underdog vs. on every favourite:
Interesting to see is that, if you had bet $10,- on every underdog for the past 10 events, you would have only lost money on one event (namely UFC Vegas 16: Hermanson vs. Vetorri). In the other 9 events you would have made profit.