One interesting aspect of the mini-blockchain scheme is that you can quickly check how many coins are left to mine because all block rewards are subtracted from the coinbase account. The address of the coinbase account is CGTta3M4t3yXu8uRgkKvaWd2d8DQvDPnpL and you can check the balance of the coinbase account like so:
listbalances 1 [\"CGTta3M4t3yXu8uRgkKvaWd2d8DQvDPnpL\"]
I checked it a few minutes ago and there were 1,843,923,137 XCN left to mine. You can calculate how many have been mined so far by subtracting the current balance from the starting balance. Since we have 64 bits of granularity and we use 10 decimal places, then the starting balance was about 1,844,674,407 XCN and the amount of coins mined so far is equal to:
1844674407 - 1843923137 = 751270
So 751k XCN mined so far if my math is correct.