Mule deer numbers are down here too, I have been watching a decline, but have seen some improvement.
Some of the decline can be explained by the Wolf population, which is really hard on Mule deer when I can find several dead Mule deer a day.

Then I think the quality and quantity of the browse has been in decline because the lack of wildfire, or controlled fire, especially in wintering area's. I see some improvement in the fire area's, but you can't just shoot them all lol, it seems hard to grow Mule deer.

Some biologist's suggest there won't be any Mule deer in the future, Val Geist recently passed away, likely the foremost authority on the subject regarding Mule deer, he wrote a number of books and his views can be found online.