As hiring picks up across the nation, more people are leaving their jobs voluntarily — a promising sign for workers, companies and the economy.

The “quit rate” — the percentage of American workers who leave jobs voluntarily — has risen to the highest level in four years. That shows that workers are more confident about finding new jobs, said Sophia Koropeckyj, a managing editor with Moody’s Economy.com.

“When people change jobs, they [usually] change to better jobs and change to higher-paying jobs,” Koropeckyj said. “When people don’t change jobs, they can be dissatisfied, and morale is low. If they’re there because they’re afraid to leave the job, that could have an effect on productivity. The ability to change jobs is a good sign in the economy.”

The number of available jobs, which plummeted to less than 2.2 million in July 2009 during the recession, has averaged nearly 3.8 million since the beginning of 2013, according to the federal Bureau of Labor Statistics.

With the expansion of the job market, more than half of the 153 organizations surveyed by consulting firm OI Partners reported higher turnover, according to research released in May. And that involved all types of jobs, including middle managers and senior-level executives.

Employers are responding — especially to supervisors and those tagged as future leaders — by offering job coaching and increasing pay and benefits, said Patty Prosser, chair of OI Partners. Front-line employees are being given improved training and perks such as tuition reimbursement and flexible schedules.

“Companies are getting aggressive with counteroffers of more money or better quality of life,” said Patrice Rice, founder of Patrice & Associates, a hospitality recruiting agency near Annapolis, Md.

“A lot are starting to put together packages for employees that are more attractive. … The job seekers are using the new job offers to get a better opportunity at their current position.”