Sometimes when you hear guys like Bill Walton waxing poetic about the NBA, one of the common themes is that there are not very many "true centers" left. You know, the back-to-the-basket, 15-rebounds-a-night bruisers. So with a guy like Shaquille O'Neal on his last legs, it left me wondering if the number of 7-footers in the NBA has changed in recent years.

In a word, no. As we can see below, the number of 7-footers in the NBA has remained relatively unchanged over the last 18-20 years.

If we track the 7-footers through the league's history. We can see that up until the early eighties, there were fewer 7-footers than there were teams. But the number of big men exploded starting around the 1980-81 season. And despite a modest increase in the number of teams, 7-footers have quadrupled in number.

Interestingly, 1979-80 is when the NBA introduced the three-point line. With players covering more space on the floor, teams may have felt a stronger need to have one big guy defending the basket.

For comparison, the history of players under six feet in height is also included. We can see that the league had almost no 5-footers until the mid-eighties. At that point, we see an influx in little men about the same time we see the spike in big men. However, that golden era of 5-footers was short-lived and in the last five years we have seen that number drop.

All data via Basketball-Reference.com