The following is extracted from the 247 Sports website.

BSU

2005 - 62 Coach Petersen

2006 - 80

2007 - 63

2008 - 87

2009 - 69

2010 - 110

2011 - 53

2012 - 61

2013 - 55  <-- 71.11 avg for nine years.

2014 - 63 Coach Harsin

2015 - 58

2016 - 68

2017 - 64

BYU

2005 - 61 Coach Mendenhall

2006 - 65 

2007 - 43

2008 - 45

2009 - 55

2010 - 33 <-- 50.33 avg for first six years prior to Utah joining the Pac-12, & BYU going Independent.

2011 - 60 <-- BYU starts Independent schedule

2012 - 71

2013 - 66

2014 - 64

2015 - 65 <-- 65.2 avg for the five years after Utah joined Pac-12.

2016 - 49 Coach Sitake

2017 - 66 <-- 57.5 avg  (sample size too small to be meaningful)

Utah

2005 - 57 Coach Whittingham

2006 - 56

2007 - 62

2008 - 61

2009 - 46

2010 - 42 <-- Avg 44.6 54 / yr prior to joining the Pac-12.

2011 - 38 <-- Joined Pac-12

2012 - 38

2013 - 47

2014 - 66

2015 - 45

2016 - 37

2017 - 33 <-- Avg 43.7 / yr since joining the Pac-12.

Virginia

2005 - 17  Coach Groh

2006 - 77

2007 - 28

2008 - 56

2009 - 33

2010 - 74 Coach London

2011 - 23

2012 - 25

2013 - 29

2014 - 33

2015 - 50

2016 - 63 Coach Mendenhall

2017 - 58 <-- 10.5 avg (sample size too small to be meaningful)

Some conclusions:

1. Bronco's recruiting dropped off big time starting in 2011, when Utah joined the Pac-12 and BYU went Independent. He never recovered from that double whammy. (I make no attempt to analyze the effect of the change in missionary age.)

2. Utah, under Whittingham consistently out-recruited BYU.

3. Utah's average recruiting ranking has barely improved since joining the Pac-12. The claim that the Pac-12 has been a great benefit for Utah recruiting is dubious. The drop off in BYU recruiting seems to be the bigger factor.

4. Since BYU recruiting rankings took a significant drop after Utah joined the Pac-12, yet Utah's rankings did not significantly improve but not as much as BYU's dropped, it can may be argued that Utah's inclusion in the Pac-12 may have opened Utah HS recruiting to schools outside of Utah.

5. Chris Petersen is a heck of a FB coach. Good record with fairly mediocre recruiting, probably due to location. Analyzing UW's rising fortunes probably would confirm this. 

6. Coach London, at UVA, was a crappy coach, but a great recruiter.

How 247Sports arrives at their rankings: The 247Sports Composite is a proprietary algorithm that compiles rankings and ratings listed in the public domain by the major media recruiting services, creating the industry's most comprehensive and unbiased prospect and team rankings.