The Office of Personnel Management has cut its backlog of unprocessed pension claims by 21 percent in the five months since it unveiled a new strategy to fix the longstanding problem. According to statistics posted online today, OPM cut the backlog by 1,150 cases in June, bringing the backlog down to 48,323 unprocessed claims. In January, when OPM announced its plan to fix its problematic pension process, the inventory was 61,108. But even though OPM has made progress so far in 2012, the size of the backlog is still far greater than it was in October 2010, when OPM Director…