As of 2009, it was 0.743%. In 1999, it was around 0.7%, and in 1989 it was 0.426%. So expecting it to hit 1% sometime this decade might be a stretch, unless the trends accelerate - it seems that the rate of increase is leveling off a bit, and hitting 1% by 2020 would be a greater increase in the next 9 years than occurred over the previous 20 (in 1991 it was just under 0.5%).

Sources:

http://en.wikipedia.org/wiki/United_States_incarceration_rat...

http://en.wikipedia.org/wiki/File:Incarceration_Rate_in_the_...

http://www.nytimes.com/1991/01/07/us/us-has-highest-rate-of-...