Answer: 12
Apollos 7-17 were manned flights. Apollo 1 is counted as a manned mission, although it never flew due to the tragedy that took the lives of its crew on the launch pad. There were several more to scheduled, but were canceled due to cuts to the space program. Apollo 17, in 1972, saw Gene Cernan and Harrison Schmitt walk on the moon, and no one has been back since.