The Ford Mustang celebrates its 57th birthday on 17 April, and there's good news for the iconic model. It's the world's best-selling sports car for the second straight year and best-selling sports coupe for the sixth year in a row.

The Mustang moved 80,577 units globally in 2020. Based on research by the industry analysts at IHS Markit, the pony car held a 15.1 percent share of the worldwide sports coupe market, which was up from 14.8 percent in 2019.

Gallery: 2021 Ford Mustang Mach 1: First Drive

The Mustang proved especially popular in Europe in 2020. The model's sales were up 68.8 percent in Hungary, versus 2019. The numbers in the Netherlands were up 38.5 percent, and Denmark saw a 12.5 percent boost.

Of the deliveries, Ford moved 61,090 units of the Mustang in the US, which was down 15.7 percent from the previous year. The model was most popular in Texas where it delivered 8,600 examples. California had the second-highest number of deliveries with 6,200 vehicles, and Florida was third with 5,864 units.

While Ford certainly had reason to celebrate the Mustang's global market share last year, the actual sales have been slipping. In 2019, the Blue Oval moved 102,090 units of the pony car worldwide, which was nearly 27 percent more than in 2020. The company delivered 113,066 examples of the car in 2018, which was almost 40 percent more than 2020.

Looking toward the future, Ford delivered 17,274 examples of the Mustang in the first quarter of 2021, which was down 4.4 percent from the same period last year. In comparison, Dodge moved 15,096 units of the Challenger in Q1, which was a 24 percent increase. The Camaro was the worst seller of the Big Three's sports coupes with a volume of 7,089 cars – a drop of 1.3 percent.