https://www.washingtonpost.com/sports/2019/01/16/onside-kicks-have-become-almost-impossible-convert-will-nfl-make-change/

Jan 16, 2019 ... Kicking teams have recovered only four onside kicks this season, ... after they recovered 13 of 60 onside kicks last season, or 21.7 percent, ...

https://www.apnews.com/a8e1a1c67f1e49088c77e9caf1afb311

Nov 21, 2018 ... Kicking teams have recovered three of 34 onside attempts this season, an 8 percent success rate that pales in comparison to last year's 23 ...

https://www.usatoday.com/story/sports/nfl/2018/11/22/successful-onside-kicks-have-nearly-disappeared/38584697/

Nov 22, 2018 ... Kicking teams have recovered three of 34 onside attempts this season, an 8 percent success rate that pales in comparison to last year's 23 ...

http://profootballtalk.nbcsports.com/2018/12/24/new-rules-have-onside-kick-recovery-rates-way-down/

Dec 24, 2018 ... So far this season NFL teams have attempted 50 onside kicks and recovered just four of them, or 8 percent. Last year NFL teams attempted 57 ...

https://en.wikipedia.org/wiki/Onside_kick

In gridiron football, an onside kick is a kickoff deliberately kicked short. On most kickoffs, the ... The onside kick is a low-percentage play, generally only seen late in a game when the kicking team is trailing in the score and must ... The kicking team may only recover and retain possession of the kicked ball, but not advance it.

https://www.theringer.com/nfl/2018/11/9/18077538/onside-kick-rules-change-strategy

Nov 9, 2018 ... To recover an onside kick, the kicking team must send the ball at least 10 yards .... The new rules should drop that percentage even lower.

http://www.optimumscouting.com/news/the-death-of-onside-kicks-why-nfl-rule-changes-may

Aug 9, 2018 ... In the first three quarters of NFL games since 2009 (including playoffs), kicking teams recovered 22 of 85 onside kicks (25.9 percent.) In the ...

http://archive.advancedfootballanalytics.com/2009/09/onside-kicks.html

Oct 21, 2009 ... The kick recovery was worth a very considerable +0.12 WP. .... the toss the best percentage play would be to try an onside kick to start the OT.

https://sports.yahoo.com/make-onside-kicks-great-replace-221940930.html

Jan 9, 2019 ... Onside kicks are nearly impossible now. ... package that's all but destroyed the trailing team's chance to recover the ball on a kickoff. ... teams attempted 566 kicks and secured 69 recoveries, an overall 12 percent success rate.

https://www.quora.com/What-percentage-of-the-time-do-onside-kicks-succeed

Pro Football Reference is a great place to find out stuff like this. This link shows all the onside kicks from this season: http://pfref.com/tiny/TGRTK ...