When the passenger slides into the back seat, there is a less than 6 percent chance that the driver on the other side of the partition was born in the United States.

And as the cab wades back into a busy avenue, there is a nearly two-in-three chance that the rider will opt not to use the seatbelt.

"Apparently all the hectoring from the taxi screen has not been enough," said David S. Yassky, the city's departing taxi commissioner and star of back-seat public service announcements imploring riders to buckle up.

The findings are among the highlights of a fact book issued by the city's Taxi and Limousine Commission on Monday, the first such study completed since 2006. Data was compiled using taxis' GPS devices and electronic surveys taken inside cabs.

Some of the takeaways were intuitive: More than 90 percent of yellow taxi pickups occur in Manhattan. Average hourly gross revenue for drivers (before lease rates for the cab and gas costs are included) reaches a peak of over $44 on Thursdays at 10 p.m. — a stretch that combines typical weeknight travel demands with heavy bar and restaurant traffic. Fares bottom out on Wednesdays at 3 a.m., with gross revenue at around $26 an hour.

But many figures seemed to counteract conventional wisdom. Mr. Yassky said he was surprised to find that many more passengers were male (49 percent) than female (34 percent). Seventeen percent chose not to answer.

"Honestly, I thought you would see more women because I think of taxi passengers often as women who feel safer taking a taxi," he said. "Maybe it's a testament to how people don't fear taking the subway."

The report also found that taxi ridership skewed much younger than the city itself. Passengers ages 20 or younger make up 35 percent of the ridership; another 35 percent said they were between 21 and 35 years old. Citywide, the groups account for 26 percent and 25 percent of the population.

Charles Komanoff, a transportation economist, cautioned that passenger surveys of this sort were often subject to selection bias. He said he was especially skeptical of the findings on riders' gender and age.

Fifty-two percent of riders said they owned a car; only a few more (55 percent) have driver's licenses at all. And more than 40 percent said their household income was at least $100,000, not including 17 percent who preferred not to answer. Only 11 percent said their household income was below $10,000.

Among drivers, demographics continue to shift significantly, according to yellow taxi licensing data. In 2005, the highest concentration of drivers (14.4 percent) came from Pakistan. Today, the top spot belongs to Bangladesh, where 23.1 percent of drivers were born, compared with 13.6 percent in 2005.

The most for-hire vehicle drivers (19.5 percent) come from the Dominican Republic.