WASHINGTON — Suicides among Army National Guard and Reserve members increased last year, even as the number of active-duty troops across the military who took their own lives dropped by more than 15 percent, according to new data. The overall totals provided by the Army, Navy, Air Force and Marine Corps give some hope that prevention programs and increased efforts to identify troops at risk may be taking hold after several years of escalating suicide rates. But the increase among Army National Guard and Reserve members raises questions about whether those programs are getting to the citizen soldiers who may not have the same access to support networks and help that their active duty comrades receive.