How many players use a belly or long putter on the PGA Tour?

Just how many players use a belly or long putter on the PGA Tour? That's the question a TaylorMade-adidas Golf staffer decided to answer.

Charlie Kautz tweeted this week a graph of how many players in each PGA Tour field in 2013 have used a belly or long putter. The results are pretty interesting.

I'm curious how a line graph showing week-by-week usage of belly, midsize, long #putters @pgatour trends after today twitter.com/CharlieTour/st…

— Charlie (@CharlieTour) May 21, 2013

— Charlie (@CharlieTour) May 21, 2013

So far in 2013, 21 is the highest number of players in a PGA Tour field to use a belly or long putter in competition. That number happened twice, at the Sony Open in Hawaii and the Tampa Bay Championship. The fewest numbers were five in the winners-only Hyundai Tournament of Champions and six players in both the WGC-Accenture Match Play and WGC-Cadillac Championship.

On average, 13.6 players have used a belly or long putter in each tournament this year, but that doesn't truly reflect the percentage of players using them as field sizes vary week to week. That number also doesn't reflect how many of those players anchor the putter under the definition of the anchoring ban covered in Rule 14-1b, to become part of the Rules of Golf on Jan. 1, 2016.

In announcing the anchoring ban on Tuesday, the USGA said no more than 2-3 percent of amateur players use an anchored stroke.