I have always been interested in how difficult it was to mine BTC in 2009, but there seems to be no clear answer.
In 2009, the difficulty was 1. The number of blocks a computer could mine at the time varied depending on many factors. A typical CPU had a hash rate of up to 3 MH/s. With difficulty of 1, that corresponds to about 60 blocks per day, which is 3000 BTC/day.
In 2010, the difficulty rose quickly as more people began mining and the number dropped.