How to get the most updated information about etherum network.

[Etherion]

Where can I find an API to calculate the price of mining etherum per day. Price = BTC/GH/DAY

Network Difficulty I can find everywhere so that is not a problem but BlockReward sees to be confusing. I always thought it was 5 ETH per block. But looking on https://etherscan.io/chart/ethersupply seems to be somehting else. 

My fomula is:

HT  = Difficulty * (Math.Pow(2.0, 32) / (1000000000000.0));
CPD = BlockReward * 24.0 * 3600.0 / HT;
Price = CPD * ExchangeRate;