In many ways, September 2017’s auto sales bucked the trend. After the industry combined for decreased volume, year-over-year, in each of 2017’s first eight months, auto sales in September rose 6 percent. Meanwhile, the shrinking car sector that tumbled 12 percent through the first two-thirds of 2017 was down only 3 percent in September.

There were two big reason the passenger car decline wasn’t worse: America’s two best-selling cars.

Excluding the Honda Civic and Toyota Camry, U.S. car sales fell 6 percent. But as the clear-out of remaining 2017 Honda Accords got underway and produced 10-percent growth, the launch of the 2018 Toyota Camry generated a 13-percent uptick. Meanwhile, the Honda Civic’s 26-percent surge allowed the compact Honda to expand its lead over the midsize Camry in the race to end 2017 as America’s best-selling car.

The Camry’s reign as America’s most popular passenger car began in 2002 and has gone uninterrupted since. At the current pace, however, the Camry’s 15-year run is set to end in 2017. The Civic’s 1,153-unit lead over the Camry through the end of August grew to 1,873 units by the end of September thanks to a 35,452-unit performance by American Honda last month.

That big Civic jump also drove the compact sedan/coupe/hatch to the top of Honda’s leaderboard, not just in September but on year-to-date terms. Slightly short supply of the in-demand CR-V produced a 3-percent downturn for Honda’s (former) best-selling model, opening up a slot at the top of the heap.

The Civic’s big improvement was also accompanied by a one-fifth loss of Fit sales, equal to roughly 1,000 fewer Fits sold in September 2017 than in the same period one year ago. Overall Honda car sales still rose 15 percent, the biggest car improvement of any major brand. Aside from niche premium outlets, only Audi, BMW, Chevrolet, Kia, Toyota, and Volkswagen reported passenger car increases in September.

With rising Honda and Toyota car sales come decreased car market share at the traditional Detroit Three. Only five of this year’s 20 best-selling cars hail from Detroit brands, which saw their collective share of the September car results fall to 26 percent from 28 percent in September 2016.

As for the Civic and Camry, which together account for 12 percent of America’s car market, Automotive News says Honda claims the imported-from-Britain Civic hatchback accounts for 23 percent of year-to-date Civic volume, with imported-from-Japan Camrys accounting for one-quarter of the Camry’s September total.

Rank Car 2017 9 Months 2016 9 Months % Change #1 Honda Civic 284,380 283,783 0.2% #2 Toyota Camry 282,507 297,455 -5.0% #3 Toyota Corolla 265,273 289,004 -8.2% #4 Honda Accord 250,802 258,619 -3.0% #5 Nissan Altima 199,861 242,321 -17.5% #6 Nissan Sentra 165,711 169,476 -2.2% #7 Ford Fusion 159,742 210,462 -24.1% #8 Chevrolet Cruze 149,234 138,012 8.1% #9 Hyundai Elantra 143,067 157,050 -8.9% #10 Chevrolet Malibu 141,162 170,389 -17.2% #11 Ford Focus 123,827 140,049 -11.6% #12 Hyundai Sonata 107,718 155,279 -30.6% #13 Kia Forte 92,092 79,608 15.7% #14 Volkswagen Jetta 90,995 89,748 1.4% #15 Kia Soul 90,727 107,823 -15.9% #16 Subaru Impreza & WRX/STI 88,745 70,241 26.3% #17 Kia Optima 84,704 89,327 -5.2% #18 Nissan Versa 82,817 106,455 -22.2% #19 Dodge Charger 67,378 72,270 -6.8% #20 Toyota Prius & Prius Prime 65,967 78,427 -15.9%

Correction: a previous edition of this list featured the Toyota Highlander rather than the Toyota Prius.

[Image: Toyota, Honda]

Timothy Cain is a contributing analyst at The Truth About Cars and Autofocus.ca and the founder and former editor of GoodCarBadCar.net. Follow on Twitter @timcaincars and Instagram.