Career isn't the only factor in determining someone's overall happiness, but it's certainly a major contributor. So, what kind of jobs do the happiest people in the U.S. have? And, how do these jobs contribute to overall happiness in life? A University of Chicago study, "Job Satisfaction in the United States," offers some insight. The study says the occupations in which people are engaged with overall happiness, not just in terms of job satisfaction, involve helping others, technical and scientific expertise, or creativity. "Happiness is determined by how much satisfaction you get from all domains of life, and work is an important domain, so it's one of the major components of overall happiness. According to the study, the top occupations in general happiness are:

1. Clergy

Job Description: Conduct religious worship and perform spiritual functions associated with beliefs and practices of religious faith or denomination. Very happy: 67.2% Median salary*: $44,102

2. Fire-fighters

Job Description: Control and extinguish fires, protect life and property and conduct rescue efforts.

Very happy: 57.2% Median salary: $45,553

3.Travel agents

Job Description: Travel agents plan and sell transportation and accommodations for travel agency customers.

Very happy: 56.5% Median hourly rate (travel agents): $14.23

4. Architects

Job Description: Plan and design structures, such as private residences, office buildings, theatres, factories, and other structural property.

Very happy: 53.5% Median salary: $54,079

5. Special education teachers

Job Description: Teach school subjects to educationally and physically handicapped students. Very happy: 52.6% Median salary (preschool, kindergarten or elementary school): $41,344 Median salary (secondary school): $43,060

6. Actors and directors

Job Description: Actors play parts on stage, television, radio, video, or motion picture productions for entertainment, information, or instruction. Very happy: 51.0% Salary varies greatly

7. Science technicians

Job Description: Use principles and theories of science and mathematics to solve problems in research and development, and to help invent and improve products and processes.

Very happy: 51.0% Median salary (research scientists): $72,435

8. Miscellaneous mechanical and repairing occupations

Job Description: Automotive service technicians and mechanics diagnose, adjust, repair, or overhaul automotive vehicles.

Very happy: 53.6%** Median hourly rate (mechanics/auto tune up): $15.26

9. Industrial engineers

Job Description: Design, develop, test, and evaluate integrated systems for managing industrial production processes.

Very happy: 48.4% Median salary: $61,729

10. Airline pilots and navigators

Job Description: Airline pilots, co-pilots, and flight engineers pilot and navigate the flight of multi-engine aircraft in regularly scheduled service for transport of passengers and cargo.

Very happy: 49.1% Median hourly rate (airline pilots, co-pilots, or flight engineers): $63.

So what is it about these occupations that spurs happiness? Clergy says he enjoys helping people and being creative.

"With ministry I get to mix my fundamental beliefs about God and life with what I do all day. So I get to work with people and assist them. And in ordained ministry I think it's a bit unique in that people will open up to you because you are a priest/pastor and reveal themselves," explains Wright, senior associate rector at The Falls Church in Virginia.

An architect with The Beck Group in Atlanta, says an important part of his happiness is due to his employer expanding his experience, and letting him have access to the construction and development sectors of the business.

A research scientist at The Nathan S. Kline Institute for Psychiatric Research in Orangeburg, N.Y., says she likes helping others: "If we can help just one person with the research we're doing, that's really rewarding. Hopefully it will help more people in the long run. A lot of time with research won't give you that, so when you can help, it really makes a difference."