During the 1960s the Department of Defense continued to scrutinize the reserve forces and to question the number of divisions and brigades as well as the redundancy of maintaining two reserve components, the Army National Guard and the Army Reserve. In 1967 Secretary of Defense Robert McNamara decided that 15 combat divisions in the Army National Guard were unnecessary and cut the number to 8 divisions (1 mechanized infantry, 2 armored, and 5 infantry), but increased the number of brigades from 7 to 18 (1 airborne, 1 armored, 2 mechanized infantry, and 14 infantry). The loss of the divisions did not set well with the states. Their objections included the inadequate maneuver element mix for those that remained and the end to the practice of rotating divisional commands among the states that supported them. Under the proposal, the remaining division commanders were to reside in the state of the division base. No reduction, however, in total Army National Guard strength was to take place, which convinced the governors to accept the plan. The states reorganized their forces accordingly between 1 December 1967 and 1 May 1968.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): How many brigades did the Secretary of Defense decrease the number to?
unanswerable