Ken Pom tracks 3 point % every year since 2002. ehre are the numbers
2002: 34.5%
2003: 34.7%
2004: 34.4%
2005: 34.6%
2006: 34.8%
2007: 34.9%
2008: 35.1%
2009: 34.2% (line was moved back this year)
2010: 34.2%
2011: 34.4%
2012: 34.3%
2013; 33.9%
2014: 34.5%
2015: 34.2%
2016: 34.7%
2017: 35%
So, this season is the second highest of all time, we are basically back to the levels we were hitting before the line was moved back.
I also did a weighted average, what I did was take the prior 3 years, and weight it 50% to the current year, 33% to the year prior, and 17% to the third year. So for example, the average for 2017 is 50% the 2017 average, 33% 2016, and 17% 2015. Obviously we need 3 years of data, so the first year for this is 2004.
2004: 34.5%
2005: 34.6%
2006: 34.7%
2007: 34.8%
2008: 35%
2009: 34.6%
2010: 34.4%
2011: 34.3%
2012: 34.3%
2013: 34.1%
2014: 34.3%
2015: 34.3%
2016: 34.5%
2017: 34.8%
So basically, the % was moving steadily up, by about a tenth of a percent per year, reaching 35% (34.98% but who's counting?), until they moved the line back in 2009. Not surprisingly, %'s went down that year, and it took a while for the moving average to catch up, and we still aren't quite at the level we were prior to the line moving out. Another year next year around 35% will get the 3 year average to right around 35%, where we were in 2008.
3 point shooting is steadily improving, which makes sense, but at the same time, we're not talking huge amounts. We allowed 863 3's this year. At 34% defense, that's 293.42 3's made. At 35%, it's 302.05. So an extra 10 3's over the course of the year. Which is a difference of 30 points, but it's really less than that, because some of those 10 threes that go from hits to misses result in offensive rebounds, and we'd give up some points off that.