I have always been interested in how difficult it was to mine BTC in 2009, but there seems to be no clear answer.

Various sources using various means of calculation come up with substantially different amounts. I've seen 100 BTC as a number, 150, 250, all supposedly from people who used regular home computers. The person who sold 10,000 BTC for $25 of pizza claimed in late 2010, twenty-two months after the Genesis Block, he was "no longer able to mine over 1,000 per day." One person online said 1,700 per day was possible with a Pentium II in 2009. There is a very big difference between 100 and 1,700 BTC per day.

Does anyone really know how many BTC someone could mine per day back in 2009 with a nice, personal home computer?

Was that same number per day still being mined in mid-2010 or had it become more difficult by that time?

Thanks!