Employees at Pfizer really love their jobs.

The pharmaceutical giant was voted the happiest company in America by its own workers for the second year running, according to an annual survey from job site CareerBliss. Health care company Kaiser Permanente took second place, followed by Texas Instruments.

To come up with its ranking, CareerBliss evaluated thousands of employee-submitted reviews across hundreds of companies. Workers were asked to rate their employers on several happiness factors, including work-life balance, company culture, compensation, and growth opportunities.

Each employee review was given an average score between one and five. These scores were tabulated to produce a company's overall rating, or "bliss score," with a higher score indicating happier employees.

Here's a look at the happiest companies in America, as well as each business's bliss score, average employee salary, and ranking on last year's list.