The VA publishes its statistics about how many cases are pending. The total number of claims pending varies between 800,000 and 1,000,000 claims, and is subject to great fluctuation.
The VA has started publishing a chart showing the time period that a veteran had served in the military. It is clear that the VA is arguing that if older veterans were not filing claims, everything would be fine. This argument is garbage; VA clearly could have anticipated the rising number of claims even prior to the OIF and Afghanistan wars if it were properly managed.
The latest VA workload report can be found here.