When my was pioneering in the 70s, the requirement was still 1,200 per year. It was pretty tough back then.
However, no one has picked up on one huge change since then, and that is the change in magazine distribution. Back then, there were two issues of both the Watchtower and Awake each month and the way many pioneers got their time in was with so-called magazine routes. Have 50 people who would take the magazines twice each month and you had massive magazine placements and a return visit for each call. We used to leave the hall with huge piles of magazines under our arms.
Pioneers would start their time with a 'route call' at one end of the territory, then walk 45 minutes to the next and then back to the other end. If the householder was out, the magazines weren't pushed through the door but another call would be made a few days later. Lots of inefficiencies but that's the way it was.