The overall Bitcoin Hashrate Network went a lot higher in the recent days, thus the difficulty has rise too the february 9th, and there was even less block rewards in the last few days. You may have the proof directly on the link below. Look at the second graph, you may know your average payout by comparing the difficulty-global network hashrate-block rewards.
Difficulty History from
https://bitcoinwisdom.com/bitcoin/difficultyDate Difficulty Change Hash Rate
Feb 09 2015 44,455,415,962 7.71% 318,224,263 GH/s
Jan 27 2015 41,272,873,895 -6.14% 295,442,739 GH/s