40 percent of those surveyed between the ages of 18-24 admit they can't concentrate without coffee.
The study also found that 37 percent of American workers drink two or more cups of coffee during their workday, ABC News reported.
The 12 heaviest coffee drinkers are:
1. Nurses
2. Physicians
3. Hotel workers
4. Designers/Architects
5. Financial/Insurance sales representatives
6. Food preparers
7. Engineers
8. Teachers
9. Marketing/Public Relations professionals
10. Scientists
11. Machine operators
12. Government workers
Source: ANI