Must be some more elections coming up.
Fall on your knees and thank Obama Almighty for getting it past those greedy Republicans!
/sarcasm
No, it's how the CPI is calculated. This time every year, the SSA looks at a "basket of goods" deemed essential, and calculates how much the price went up in the previous year.
Three years ago, in 2008, we were just past the peak of a fast rise in gasoline prices. They were even higher than they peaked this year, due to the supply disruptions by Hurricane Ike. As a result, Social Security recipients got a big CPI increase at the beginning of 2009: 5.8%. The price of gasoline crashed after that.
But, the new price baseline was set. Since oil products are a big component of that "basket of goods", the calculation actually yielded a decrease in the CPI for the next two years. But, the SSA doesn't reduce benefits: it just freezes them until the CPI catches up. It finally caught up this year.
The truth is: Social Security recipients got their CPI increase for 2009, 2011, and 2011 all at the same time in 2009. They have actually done better than if the CPI increases had been incrementally spread out over the three years, because recipients have been getting the higher benefit payment for the entire time.