Aroldis Chapman recorded the 100th save of his major league career last night – a milestone that divides Reds fans into Team Celebrate and Team Lament. Putting aside the controversies about how the organization has used Chapman, it’s a fitting moment to recognize that the 26-year-old is in the midst of an unprecedented, historic season.

Here’s why: Of the 124 batters the Cuban Missile has faced, he has struck out 67.

That’s a strikeout-rate of 54 percent.

If Chapman finishes the year with that number, it would represent the highest single-season strikeout-rate, dating back to 1901 for pitchers who’ve thrown at least 40 innings. Only one has finished a season with a K% above 50 percent and that’s Craig Kimbrel of the Atlanta Braves who struck out 50.2 percent of the batters he faced in 2012.

As you marvel at Chapman’s accomplishment, contemplate 54 percent in this historical context:

• Nolan Ryan’s best full-season (1987) strikeout-rate was 30.9 percent. Sandy Koufax’s best (1965) was 29.5 percent.

• 1968 was The Year of the Pitcher. It featured high pitching mounds and an enforced strike zone from the armpits to the knees. And in the The Year of the Pitcher, Bob Gibson was Pitcher of the Year, winning the NL Cy Young unanimously. That season, Gibson’s ERA was 1.12 and FIP was 1.77. His strikeout-rate was 23.1 percent.

• Mariano Rivera’s career strikeout-rate was 23 percent and highest single season was 30.6 percent.

• Clayton Kershaw is striking out 33.3 percent of batters he faces this year. Johnny Cueto’s K% is 25.7 percent.

• Rob Dibble had four healthy, full seasons in the major leagues. In each of those years, 1989-1992, he led baseball in K%. In 1992, Dibble beat fellow reliever Dennis Eckersley by 8 percent. Eckersley won the AL Cy Young Award that year. The Eck’s strikeout rate was 30 percent.

• In 1990, Dibble, Randy Myers and Norm Charlton – the Nasty Boys – were in the top five in baseball in K%. Their average K% was 30 percent.

• In 2003, PED-fueled Eric Gagne led the major leagues with 55 saves in 55 opportunities. He won the Cy Young Award as a reliever. Gagne also led baseball with a 44.8 percent K%, 10 percent ahead of second-place Jose Valverde.

• In 2010, Chapman’s first major league season, Carlos Marmol led baseball with a 41.6 percent strikeout-rate. The year before, Jonathan Broxton led the majors with a 38 percent K-rate.

To be certain, the number of strikeouts is growing all across baseball. The strikeout rate was 13 percent in 1975 and has risen steadily to 20.3 percent in 2014. It stood at 15.8 percent in The Year of the Pitcher. So seeing individual pitchers with ever higher K% isn’t unexpected.

But even in this era of K-inflation, Aroldis Chapman stands apart. If the season ended now, the gap between Chapman’s league-leading strikeout-rate and the second-best (Kimbrel, 43.3 percent) would be the largest ever.

What has caused Chapman’s strikeout-rate to jump from the low-40s to the mid-50s? Take your pick. His average fastball is faster this season and he’s throwing it up farther in the strike zone. His slider is better-located and he’s throwing it 26 percent of the time compared to a career rate around 14 percent. Or maybe it’s the new change-up that he’s throwing for 10 percent of his pitches. Hitters have only put it in play once. Why is Chapman better? It’s any of those factors, or all of them.

Aroldis Chapman has only thrown 33 innings this season and he’ll probably end up in the neighborhood of 55. Chapman still has two months to go before he actually sets the record for the single most dominant season in the history of relief pitching, by that measure.

That Chapman is pitching at all in 2014 is remarkable given his spring training mishap. But Chapman’s 2014 performance is an impressive continuation of a fabulous strikeout career. Nolan Ryan holds the single-season record (1973) for strikeouts with 383. Chapman has 391. Ryan pitched 326 innings that year. Aroldis Chapman has pitched 232.