The Social Security Administration has released its "waterfall" chart for Fiscal Year 2010. These are very recent statistics.
At the Initial application level, on a nation-wise basis, 35% of disability claims were allowed, and 65% were denied. At the Reconsideration level, of the denied claims that were appealed, just 13% were allowed, and 87% were denied again.
Note how the allowance rate increases at the hearing level. 62% of the claims that are appealed to the hearing level were allowed. That is why it is so important to appeal your denial.
It is also worth noting, on the bottom row of the chart, that 51% of federal court appeals were remanded or allowed. That's a high number.
You can see the statistics for the previous year in the 2009 waterfall chart.