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 CPU miner had a hash rate of up to around 3 MH/s. With difficulty of 1, that corresponds to about 60 blocks per day, or 3000 BTC/day.
In 2010, the difficulty rose quickly as more people began mining, and so the number dropped. By the end of 2010, the difficulty was around 15000, so that same 3 MH/s CPU miner only mined 0.2 BTC/day.
BTW, the average time between blocks can be estimated with this:
time in seconds = difficulty * 232 / hash rateFascinating, thank you.