Clarke questioned whether the city is cutting too many benefits too quickly.

"Why try to save [money for] city government 20 years out on the backs of our employees and retirees?" Clarke asked. "Everyone has already experienced in this year's budget a radical increase in our personal obligations to health care. I think this is excessive."

A consultant for the city found Baltimore offers greater pension benefits than other local jurisdictions.

The consultant reported that a city worker making $40,000 a year earns an average of $4,664 in pension benefits annually, compared with $4,326 for a worker in Howard County, $3,324 for a state worker, $3,194 for Anne Arundel, $2,665 for Harford, $2,650 for Baltimore County, $2,502 for Prince George's, and $2,315 for Montgomery.

Draine, the Pew researcher, said Baltimore's pension system was relatively well-funded several years ago, but that changed during the economic downturn.

When he studied 61 cities' pension systems in 2009 — among which he found a $217 billion cumulative funding gap — he rated Baltimore's pensions among the best-funded in the country.

Today, however, Baltimore's pension system for municipal employees faces $681 million in unfunded liabilities, according to city documents. The system, which was fully funded in 2003, has weakened each year and is now only 67 percent funded.

Stokes said proposed changes to pensions reflect a changing American workforce. While the municipal employee of decades ago might expect to stay with city government for years and count on a solid retirement, younger workers of today might plan on staying in a position for only a few years.

In Baltimore, city workers are eligible to retire after 30 years on the job or at age 65. Though workers accrue their pensions at varying rates, an individual can expect to receive more than half of his or her salary on average in retirement.

The pension legislation is part of a 10-year plan Rawlings-Blake says is needed to fix city finances. The mayor wants to eliminate a projected long-term $750 million budget shortfall while cutting property taxes by more than 20 percent and raising salaries by 10 percent over the next five years.

She has said that city government is weighed down by "outdated" benefits that "have crippled our ability to pay workers what they truly deserve in their paychecks."

Later this year, the mayor has said, she will introduce additional legislation to create a 401(k)-style retirement plan for new civilian city employees and a "hybrid" plan for new firefighters and police.