The top wellness benefit that workers want is a fitness center discount, but these discounts are not the top benefit offered by employers, according to the latest Principal Financial Well-Being Index.

The top four wellness benefits that workers would most like to see their employer offer are fitness center discounts (25 percent), on-site preventive screenings (22 percent), access to wellness experts such as nutritionists (21 percent) and onsite fitness facilities (19 percent), according to the index, which surveys American workers at growing businesses with 10 to 1,000 workers. However, the top four wellness benefits offered by employers are online wellness information (19 percent), educational tools or resources (18 percent), fitness center discounts (17 percent) and printed wellness information (17 percent). Access to wellness experts was available to 11 percent of those surveyed.

The survey, which was conducted by Harris Interactive for global investment management company Principal Financial Group, found that Americans work harder, are more productive and miss fewer days of work if they participate in wellness benefit programs. Forty-one percent of the workers surveyed agree that having a wellness program encourages them to work harder and perform better at work.

According to the research, 52 percent of workers (up from 37 percent last year) said they have more energy to be more productive at work by participating in a wellness program. Another 35 percent (up from 28 percent a year ago) said that they have missed fewer days of work by participating in a wellness program.

“Americans’ increasing sense of personal responsibility for their physical well-being leads to workers showing up to work and staying productive while there,” Lee Dukes, president of Principal Wellness Company, a subsidiary of the Principal Financial Group, said in a release about the report. “Employers who embrace a culture of wellness in their workplaces can benefit in return with not only costs-savings but healthier and more engaged employees.”

Forty-five percent of workers chose better overall physical health as the top benefit to participating in a wellness program. Other top mentions included receiving a meaningful incentive from their employer for participation (30 percent) and reduced personal health care costs, greater chance of living a longer, healthier life and reduced stress (29 percent each). Fifty-five percent of workers rated wellness activities offered by an employer as very successful or somewhat successful in improving health and reducing health risks.