Across the United States, there are close to 200 million registered cars, but most of them have roofs. Boring! You probably know that convertibles are more interesting than your typical automobile, but in the latest installment of “Stuff You Didn’t Know,” we hope you learn a couple of other exciting facts, such as…

1. At First, Convertibles Weren’t Really Novel

The convertible as a novelty presupposes that cars have roofs, but that was not initially the case. Most early cars were much more open than today’s vehicle and didn’t have roofs or sides.

2. They make up roughly two percent of the auto market

After dominating the market in the early days of the automobile, convertibles have ebbed and flowed, dipping below 1 percent in the 1930s and jumping past 5 percent in the 60s. Now, they make up about two percent of the market.

3. They’re most popular in Florida

Most cars have roofs. People going out of their way to buy cars without roofs better live in a good climate, and, in fact, they do. Florida is the only state in which more than 3 percent of cars are convertibles. On the flip side, the only state where less than 0.5 percent of cars are convertibles is Alaska.

4. A/C and Car Stereos Helped Lead to Their Diminishing Popularity

In the 1960s, convertibles were making a comeback. But modern cars just don’t jive with the outdoor experience. When cars began being outfitted with air conditioning and stereo systems — neither of which is optimized for the outdoor convertible environment — roofs once again became more attractive.