Americans have a growing crush on manual transmissions.

To be sure, the percentage of new vehicles with stick-shift gearboxes remains a small slice of the new vehicle market, because most of today's models don't even offer manuals.

But the first quarter this year manuals were in 6.5% of new vehicles sold, and that's getting close to double each of the past five years. It's also highest since 7.2% in 2006, according to Edmunds.com.

That high "take rate," as the industry calls it, is even more impressive because just 19% of the 2,360 different models on sale offer manuals, Edmunds.com reports. Five years ago, 29% of the 2,391 available styles did — yet only 2.9% were sold with stick shifts that year, the lowest "take rate" in a decade.

Manuals no longer are the safe-bet mileage champs. They often do much worse, in fact, than today's computer-controlled, mileage-tuned automatics. Instead, the lures of a car with a clutch pedal are:

• Price. Manuals typically are at least $1,000 less than similar models with automatics. Manuals are most readily available in the increasingly popular small, lower-price cars whose buyers often are especially price-sensitive.

• Performance. Many people consider manuals more fun to drive than automatics. And even those who don't often see them as a way to wring the most pep possible from the small-engine, low-power cars that are getting more attention because they use less fuel and cost less to buy. "In these compact cars, it's easier to get the most power from the manual," says Ivan Drury, analyst at Edmunds.com.

• Habit. People who've been driving sticks are back in the market and buying them again. The average age of a trade-in is a record 6.1 years, Edmunds.com data show. That coincides with the last time — 2006 — that manuals had a robust "take rate."

• User-friendliness. Modern manual-shift gearboxes have much easier-to-use clutch pedals than ever. Today's clutches take less effort to push and release. And they engage smoother, making it less likely a driver will kill the engine in traffic or subject passengers to jerks and stumbles on every shift.

The jump in interest surprised automakers: