.0312 if difficulty increases 5% each time
.0208 if difficulty increases 7.5% each time
.0156 if difficulty increases 10% each time
.0078 if difficulty increases 20% each time
based on that the difficulty in 1 year (june 2014) will be around
83 million (5%)
169 million (7.5%)
336 million (10%)
4581 million (20%)