In March 2016, check out Timothy Bella’s “Life After Concussions in College Sports” panel at South by Southwest Update (Dec. 31, 2015): Hours before the College Football Playoff, Oklahoma announced that defensive lineman Charles Walker was out due to a concussion suffered earlier in the week. The numbers below reflect the news. Numbers define the College Football Playoff, the NCAA’s attempt at a playoff system for major college football. Four teams. Three games. One true champion. More than $500 million in bowl revenue. But there’s another number that’s not widely publicized, if at all: 501, the number of publicly reported concussions in major college football in the last three seasons. The figure, which has been collected from data over the last three years, highlights a public knowledge gap in just how often concussions occur in college football. In the 2013 through 2015 seasons, each of the more than 120 schools in the NCAA Football Bowl Subdivision (FBS) has publicly reported an average of four concussions — a little more than one per season. Yet, during the 2015 season alone, there were 166 publicly reported concussions in major college football, according to the America Tonight concussion map, an annual database compiled from college football concussion data for all the FBS programs for the last three seasons. That’s an increase of about 15 percent from the 2014, but still 15 percent lower than 2013, which had 192 instances of reported head trauma in college football. That information helps quantify a part of the much bigger story centered on concussion reporting in college athletics: The number of concussions in major college football that are publicly reported or acknowledged by coaches and athletic departments is still only a small fraction of the thousands of concussions that happen every season.

For the second consecutive year, more than 60 programs — nearly half the schools in major college football — didn’t publicly report a concussion

2015: 61 schools 2014: 62 schools 2013: 42 schools During the 2015 season, 61 of 128 FBS programs, or 48 percent of schools in major college football, didn’t publicly report a concussion. This was only a slight change from the 2014 season, when 62 of 125 FBS programs didn’t publicly report a concussion.

Fifty-six percent of current top 25 teams didn’t publicly report a concussion

2014: 40 percent 2013: 44 percent If you were a ranked team by the end of the 2015 season, you were less likely to have publicly reported a concussion than you would have been in 2013 or 2014. Fourteen programs in the final top 25 poll of the regular season didn’t publicly report a single concussion for 2015. Ranked programs included No. 1 Clemson, No. 5. Iowa, No. 6 Stanford, No. 7 Ohio State and No. 12 Ole Miss, all of which are playing in New Year’s Six bowls, college football’s most lucrative and prestigious matchups.

Fourteen percent of publicly reported concussions came from current top 25 programs

2014: 22 percent 2013: 6 percent Ranked teams made up a sizable portion of publicly reported concussions in 2015, but that rate took a dip compared with 2014. Florida State had nine of the 23 publicly reported concussions among top 25 teams, accounting for close to 40 percent of concussions for ranked teams.

Twelve players were forced to retire because of concussions in 2015

More All-Americans suffered more publicly reported concussions than any other time in the last three seasons

Baker Mayfield, left, and Ryan Kelly are both headed to the College Football Playoff. They both have also suffered publicly reported concussions this season. Steve Nurenberg/Icon Sportswire via AP Images; Butch Dill/AP 2015: Four 2014: One 2013: One Included in this year’s list of publicly reported concussions were four of the nation’s most decorated players. Two of the players – Oklahoma’s Baker Mayfield and Alabama’s Ryan Kelly – are playing in this year’s College Football Playoff. The other two players – Robert Nkemdiche of Ole Miss and Jourdan Lewis of Michigan – were both second-team All-America selections. In the 2013 and 2014 seasons, only two All-America selections – Florida State’s Bryan Stork and Rashad Greene – suffered publicly reported concussions.

With at least 12 publicly reported concussions, the University of Wyoming was this year’s concussion king

2015: 12 at Wyoming 2014: 10 at Colorado 2013: 9 at Hawaii For the third consecutive year, a team with at least 10 losses led the way, with the number of concussions going up each year for each program. This year, it was Wyoming, with a record of 2-10 and 12 publicly reported concussions. That total could actually be higher, with local media estimating the number of concussions for Wyoming to be somewhere in the 20s.

The ACC, with its 27 reported concussions, led all conferences in 2015

2015: 27 in the ACC 2014: 25 in Mountain West 2013: 26 in Mountain West After two straight years of the Mountain West conference leading reported head trauma, the ACC stepped ahead, publicly reporting a dozen more concussions than it did in 2014. Among the 10 conferences and the independent programs in the FBS, the ACC also had nine of its 14 programs publicly report at least one concussion, a conference rate beat only by the Big 12.

Even with only two concussions each, Oklahoma and Houston accounted for two-thirds of publicly reported concussions among conference champions

2015: Two at Oklahoma, two at Houston 2014: Seven at Florida State 2013: Six at Florida State Across the board, concussion reporting among conference champions was way down in 2015, which produced just six publicly reported concussions from the 10 conference champions. In 2014, the total was 15, with Florida State leading the way. With nine concussions in 2015, the Seminoles actually recorded more concussions this year than any time in the last three years, but when Clemson won the conference, it disqualified Florida State from the category.

Aside from Oklahoma, all the programs in this year’s College Football Playoff reported no more than one concussion each

The coaches of the four programs in this year's College Football Playoff. Gaston De Cardenas/AP; LM Otero/AP; LM Otero/AP; Lynne Sladky/AP Only Ohio State publicly reported having a concussion before the 2014 CFP It’s not looking good for the college football’s final four. For Clemson, this year’s top-ranked team, 2015 marks the second consecutive year in which the Tigers didn’t publicly report a single concussion. Their CFP comrades aren’t faring much better. It’s the third straight year Alabama has recorded just one concussion. Michigan State’s lone concussion in 2015 is actually an improvement from the two previous years of not publicly reporting a single one. And before the Sooners announced a key defensive lineman would miss the Orange Bowl with a concussion suffered earlier in the week, Oklahoma, like Alabama, had publicly reported just three concussions in the last three years.