Okay, looks like I've figured it out and messed w/ '18 for a single season of review.
In 2018 there were 84 UDFA rookies who graded out in AV (Pro football reference's composite measurement). They totalled 159 'points' and were led by...well of course you guessed it....Andrew Wylie and his 8. It's not a perfect analysis because Wylie was a rookie but was technically eligible for the 2017 draft. But in either event, he was a UDFA who went undrafted and thus could've been on anyone's roster.
In the 6th and 7th rounds there were 38 rookies who 'scored' and they totaled 67 'points'. If I include the 5th round that's another 29 scoring rookies and 52 points. So from the 2018 draft there were 67 rookies taken in rounds 5-7 who 'scored' via the AV system. They contributed a total of 119 points.
The UDFAs absolutely wreck those numbers.
Seriously, teams wildly under-utilize the UDFA pool and in so doing overvalue their picks in the 5th, 6th and 7th rounds. Punt those picks, use them to move up in the other rounds and simply take those roster spots and allocate them to the 'winners' of the an annual roster competition among a larger pool of UDFA players.
Here's the little stat machine that can figure this out if you want to do it over a number of years.
https://www.pro-football-reference.c...psl_finder.cgi