WASHINGTON (Reuters) - A record 64 percent of U.S. private sector workers are now entitled to sick leave, marking a steady rise in the past decade, the Labor Department said on Tuesday.

The increase has come as five states, the District of Columbia and 28 localities have enacted legislation in recent years mandating sick leave for workers. Chicago's city council unanimously passed a bill last month that allows workers to earn days off for illness.

The Labor Department said in a blog post that the percentage of workers with at least one day of sick leave had risen 3 points in the past year, and is up 7 percentage points since 2006.

Melissa Josephs, the director of equal opportunity policy at Women Employed, which backed the Chicago leave measure, said paid sick leave showed the value of government action to address workplace issues.

"It's better for workers, for employers, it's better for the economy," she said.

The rise from 2015 to 2016 was mostly due to an increase in access for workers with average wages in the bottom 25 percent. The share of workers with paid sick leave in that segment rose to 39 percent this year from 31 percent in 2015.

Inequality in sick leave still remains, with employees in the top quarter of wages 2.2 times more likely to be able to get paid leave than those in the bottom fourth. But that gap has narrowed from 2.7 times in 2015, the department blog said.

(Reporting by Ian Simpson; Editing by Bill Trott)