It would be hard to calculate the exact percentage because due to the BitGun reward feature, the reward per block varies depending on how much hash is on the network. If we were stuck at bitgun level 1, the yearly rewards would be about 1,524,240 coins.(4 coins per block per minute.) So after a year, that would be about 38%. (970000/((1524240+970000.) However, we are currently at bitgun level 4 (9 coins per block) and have been higher than that, so the percentage to yearly POW would be lower.

(I know that I am not the OP. But I thought you would prefer a prompt answer.)

Also keep in mind that the XDNA foundation gets 2% of the block reward for every block. (The XDNA foundation is supposed to be for charity.) Also 1% of every block goes direct to the development team.