What’s the most significant loss for the Blackhawks in the three seasons since their last Stanley Cup championship?

Forget about players and playoff series, or even the postseason berth they failed to earn this year for the first time in a decade. It’s local TV viewers, who have bailed on the team in droves.

The Blackhawks’ cable TV ratings on their home outlet have plummeted 45 percent in those three seasons, from a 4.3 average household rating in the Chicago area in 2014-15 to 2.36.

Combined with there being fewer TV homes in this market, that represents a loss of 71,708 local homes, per Nielsen estimates.

The Hawks averaged 149,521 households watching their games on what was then called CSN in 2014-15, but just 77,873 had the games on the rechristened NBC Sports Chicago this season.

Those numbers don’t count the games cherry-picked for national TV or WGN-9. But as a benchmark of viewer interest and audience trends, it’s not pretty.

The Blackhawks remain a big draw at the United Center, continuing to lead the league in average home attendance. This season they averaged 21,654, which is 109.8 percent of seating capacity, also tops in the NHL.

Also, even in decline, the Hawks still have more households watching them on their local regional sports network than any other American NHL team.

The Penguins have the NHL’s highest local household ratings among U.S. teams, averaging 5.81 percent of Pittsburgh-area TV homes. But Pittsburgh is the nation’s No. 24 market, so that represents only 66,437 homes.

The Bruins, No. 5 in local ratings with a 2.95 household rating in the No. 10 Boston-Manchester, N.H., market, are runners-up to Chicago in average households with 71,500.

But household TV ratings in the third-ranked Chicago market for the Blackhawks in 2017-18 were down 29 percent from 2016-17, which was down 16 percent from 2015-16, which was down 8 percent from 2014-15.

The 2.36 average household rating this season, or 2.36 percent of all TV households in the market, is the team’s worst local cable performance since 2008-09, when the Hawks averaged a 1.26 average household rating or just 44,010 homes.

That was when the Blackhawks began a run of nine straight postseason berths that ended this spring. It also was the first season they put their entire schedule on TV. Both were critical factors in the franchise’s rebirth and rise in popularity.

Chairman Rocky Wirtz, who took over the team from his late father, Bill, the season before, moved quickly to reverse the long-standing and long-puzzling anti-TV policy by televising a handful of home games on local TV in 2007-08.

At the time, the Hawks’ average household TV rating that season was a scant 0.63, or 21,855 homes, while average United Center attendance was only 16,814.

That provides some indication of what the organization had built and how quickly the Jenga tower of fan support can be shaken and come crashing back to Earth.

Blackhawks local cable ratings peaked in the 2012-13 season with 5.38 household average, or 187,482 homes, but that was buoyed by two anomalies.

First, there was an abbreviated 48-game season because of a league lockout. Second, the Hawks got off to a phenomenal 21-0-3 start in the first half en route to their second of three championships in six seasons.

Last season on NBCSCH started on a high note, a 5.12 household rating for the opening victory over the two-time defending champion Penguins. But of the last 20 Hawks telecasts this year, a run that began in February, they lost 16.

Some teams can weather that kind of mediocrity and sustain their ratings. The Blackhawks clearly cannot.

They did better than their also-struggling United Center stablemates, the Bulls, whose local cable numbers declined 10 percent from a 2.0 rating in 2016-17 to 1.8 this past season on NBCSCH.

That’s below the NBA’s leaguewide average on local regional sports networks this season, which was a 2.4 rating, a 4 percent season-to-season increase. Total viewership for NBA national regular-season telecasts — on ABC, ESPN, TNT and NBA TV — was up 8 percent from a year ago to 1.28 million people.

What all teams aspire to be is a franchise that somehow has amassed a dedicated fan base that remains engaged even as losses mount and insulated from when their sport or league seemingly falls from favor.

That would be the Bears.

Despite the NFL’s average total viewership falling 9.7 percent from 16.5 million people in 2016 to 14.9 million, the Bears’ broadcast and cable household ratings rose 4 percent in the Chicago market last season, from an 18.6 average household rating in the 2016-17 to 19.4.

The Chicago market’s reduced size means the Bears were on in almost 4,000 fewer homes even with the better rating, but that's a decline of only 0.6 percent in an audience that continues to exceed 640,000 local households each game.

Imagine what some enthusiasm for new Bears coach Matt Nagy and a few victories might do.

Meanwhile, if the Blackhawks failing to make the Stanley Cup playoffs this season has helped anyone, it may be the local baseball teams. Without even a first-round four-game ouster to compete against, their NBCSCH ratings are up for the Cubs and White Sox despite disappointing starts.

Heading into the weekend, the Cubs' local cable household ratings were up 20 percent compared with the same point last season, from 3.5 to 4.2. White Sox ratings were up 38 percent from 0.8 to 1.1. The number of unique viewers for each team’s games via the NBCSCH live stream is up as well.

The ballclubs have been playing in hockey weather, while the Blackhawks have a few months to try to figure how to get viewers to warm to them once again. Winning would be a good start.

philrosenthal@chicagotribune.com

Twitter @phil_rosenthal