In these 10 cities, many out the door by 5 a.m.

If you commute in one of these cities, we hope you like coffee.

A study found that these 10 metro areas on average had the highest percentage of commuters leaving before 5 a.m. among the top 50 largest metropolitan statistical areas (as defined by the Office of Management and Budget):

1. Riverside-San Bernardino, Calif.: 9.9%

2. Phoenix: 7.1%

3. Las Vegas: 6.9%

4. San Juan, Puerto Rico: 6.2%

5. Seattle: 5.3%

6. New Orleans: 5.2%

7. Los Angeles: 4.9%

8. Birmingham, Ala.: 4.8%

9. Chicago: 4.6%

10. Houston: 4.5%

Roughly 1 in 10 commuters in Riverside-San Bernardino, Calif. (east of Los Angeles), leave before 5 a.m.

The study – conducted by Best Mattress Brand, which researches and reviews mattress brands and sleep issues – used data from the Census Bureau’s American Community Survey between 2009 and 2015.

Many workers, especially in large cities, have commutes that are 30 minutes or longer one-way.