What was the total number of missions conducted by the entire Space Shuttle fleet from 1981 to 2011?

Answer

135 missions

Across its lifespan, the Space Transportation System (STS) era saw the fleet conduct a combined total of 135 orbital missions.

What was the total number of missions conducted by the entire Space Shuttle fleet from 1981 to 2011?
NASAMissionsSpace Shuttleflights