The numbers for US troops deployed to Vietnam during the same period were quite different, 2,000 in 1961. rising rapidly to 16,500 in 1964.
The National Security Council recommended a three-stage escalation of the bombing of North Vietnam.
Following an attack on a US marine barracks at Pleiku , Operation Flaming Dart, Operation Rolloing thunder, and Operation Arclight commenced.
The bombing campaign, which lasted for three years, was intended to to force North Vietnam to cease its support for the National Front for the liberation of South Vietnam by threatening to destroy air defenses and industrial Infrastructure.
After several attacks upon them, it was decided that US air force bases needed more protection.The US military was increased from 3,500 to nearly 200,000 by Dec. Beginning in 1970 American troops were being taken away from border areas where much more killing took place and instead put along the coast and interior which is one reason why casualties in 1970 were less than half of 1969's total.