Veterans Affairs Department officials pledged Wednesday that its backlog of benefits claims will begin to shrink, with hopes for a modest 5 percent improvement by the end of the year and a more significant drop in 2013 as changes in claims handling and employee training take root.

Progress might have come sooner if not for the fact that disability benefits claims are becoming more complicated all the time.

Allison Hickey, the retired Air Force brigadier general who serves as VA’s undersecretary for benefits, said the average claim now includes 15 separate disabilities for which a veteran is seeking compensation, a change from days when veterans had one or two disabilities.

Hickey said the backlog includes 911,000 pending claims, 597,000 of which are more than 125 days old.