have u looked at a bitcoin calculator
If it wasn't for this I would say with 100% certainty that OP was trolling. There are a lot of calculators in the wild with per year decreases in profitability.
This one even has BFL ads. lol:
http://www.bitcoinx.com/profit/
Default 60% decrease of profitability per year....
I got 400 % decrease in a month, are you sure this is right?
Yeah, I'm sure that calculator rules and 60% depreciation a year is right. You just proved to me that OP doesn't need to be a troll and reduced my faith in humanity just a little bit more.