From the May 2016 issue
The numbers are in and it?s official: 2015 was the auto industry?s best year in history. Automakers sold 17,470,659 cars, light trucks, and SUVs in the U.S. last year, surpassing the record set in 2000 by more than 68,000 units. Between 2001 and 2007, sales had been on a gradual decline, and when the recession hit in 2008, they plunged into the abyss, hitting a low of 10.4 million units in 2009.

This graph of annual sales shows the long, hard climb out of 2009. Analysts predict that sales will hold strong through 2018.

THE THREE WHYS, MAN

A complex web of factors influences car sales. Here?s how three of the biggest?the unemployment rate, interest rate, and the Consumer Confidence Index?relate to the sales totals over the past 10 years:
LOTS OF LUXURY

Not only was 2015 the best year for the auto market as a whole, but luxury automakers did better than ever before, too. A 0.5-percent gain since 2011 doesn?t sound like much, but in terms of volume, it?s more than 600,000 additional vehicles. Land Rover realized the strongest growth, increasing sales from 26,000 in 2011 to about 70,500 in 2015. IHS predicts that luxury sales will account for 13.5 percent of the market in 2020.

Analysts say a variety of factors have coaxed the sales bull out of hibernation. The most obvious one has been low fuel prices. Gasoline averaged $2.52 per gallon in 2015 and is already lower this year. Sources such as the International Monetary Fund and the World Bank...