Total Number of Vests on The Steem Blockchain

I'm still working out the mechanics behind the Steem blockchain assets, and I have the following questions regarding vests (i.e. Steem Power):

1. Is there a way to figure out the total number of vests on the network?
2. Is the number of vests limited, or does that value continue to grow?
3. If the number of vests grow over time, what protects holders of vests from dilution?

Thanks!