3 Pointers in the NBA

So apparently, the amount of 3 point shots have gone up over time in the NBA:

http://espn.go.com/nba/playoffs/2015/story/_/id/12993098/nba-35-year-war-3-pointer

The question is, why?

Here is what I am thinking:

1. We could look at the data and correlate the increasing diversity in the NBA with increased 3 point shots. 

2. We could also analyze the correlation of a shortened 3 point line and the accuracy of the 3 point shot.