AH-1 Cobras were in use by the Army during the Tet offensive in 1968 and through to the end of the Vietnam War. Cobras provided fire support for ground forces, escorted transport helicopters and other roles, including aerial rocket artillery (ARA) battalions in the two Airmobile divisions. They also formed "hunter killer" teams by pairing with OH-6 Cayuse scout helicopters. A team featured one OH-6 flying slow and low to find enemy forces. If the OH-6 drew fire, the Cobra could strike at the then revealed enemy. On 12 September 1968, Capt. Ronald Fogleman was flying an F-100 Super Sabre when the aircraft was shot down and he ejected 200 miles north of Bien Hoa.  Fogleman became the only pilot to be rescued by holding on to an Army AH-1Gs deployed gun-panel door. Bell built 1,116 AH-1Gs for the U.S. Army between 1967 and 1973, and the Cobras chalked up over a million operational hours in Vietnam; the number of Cobras in service peaked at 1,081. Out of nearly 1,110 AH-1s delivered from 1967 to 1973 approximately 300 were lost to combat and accidents during the war.  The U.S. Marine Corps used AH-1G Cobras in Vietnam for a short time before acquiring twin-engine Bell AH-1 SuperCobra.. Approximately how many of the 1110 AH-1s delivered from 1967 to 1973 were lost per year on average?