Thoughts on the California beaver population

We’re killing beavers all over California, and more every year. Does this mean there are more beavers? Or that we’re encroaching on more of their habitat? Here’s a slide I whipped up a while ago:

It’s pretty crude, so anybody with a statistics background feel free to pick this apart in the comments—I’d love to make this piece a little more robust. Anyway, I used APHIS kill numbers from their website (click a year, scroll down and click PDR G) to build the chart. Since there’s no current data on total population, I wonder if there’s any possible extrapolation from kill numbers, even to within an order of magnitude. Probably not, so let’s try to make relocation legal as soon as possible. California’s dehydrated, streams are getting flashier all the time, and what, exactly, does LA plan to drink when the Sierras are dry? Thoughts?