The United States will suffer high unemployment for some time as it slowly recovers from the deep recession that ended in 2009, a former second in command at the Federal Reserve said on Wednesday.

I see a very slow, uneven recovery. It will not be fast enough to put a dent in the painfully high unemployment rate for some time, Roger Ferguson, the Federal Reserve's vice chairman from 1999 to 2006, told Reuters after a speech in Cambridge, Massachusetts.

Ferguson's prepared remarks at a National Bureau of Economic Research event focused on the fragile state of Americans' retirement savings and the concerns it poses for policymakers.

For too many people, financial security that lasts a lifetime is beyond their reach, said Ferguson, now chief executive at the financial services company TIAA-CREF.

U.S. consumers' worry about long-term financial stability has been magnified over the last two years by ongoing market turmoil, Ferguson said.

Meanwhile, the replacement for many workers of company-provided pensions with savings schemes like 401(k) plans has removed an element of security from most Americans' retirement equation, he added.

Employers, by contrast, have benefited substantially over the past three decades by jettisoning defined benefit pensions.

Ferguson also noted that about 50 percent of U.S. workers do not have access to an employer-sponsored retirement plan, and of those, only a fraction have an individual account such as an IRA.

Besides leading the largest U.S. private retirement system, Ferguson serves on President Barack Obama's Economic Recovery Advisory Board, a panel assembled to advise the White House on potential responses to current economic conditions.

Ferguson noted that the United States is at a pivotal moment in the debate about retirement security.

Social Security, the government safety net that has provided an income floor for retirees since the 1930s, will soon pay out annually more than it collects.

It is unclear when policymakers will develop an appetite for making difficult choices to return the system to more stable footing, Ferguson said.

Inadequate saving by many U.S. workers has long been a topic of concern in the financial and policymaking communities. But with some 76 million Baby Boomers exiting the job market over the next several years and starting to draw down their savings, financial shortcomings may be unavoidable.

Ferguson said saving between 10 and 15 percent of gross annual income is the first step to having a standard of living in retirement near that of one's working years.

A lack of preparation to pay what are often staggering medical expenses during retirement is one of the fastest ways to eat through savings, he added.

Ferguson said that guaranteed income in the form of annuities, which pay out a defined sum on a regular schedule, is a way for many to increase their prospects of long-term retirement security.

TIAA-CREF, which specializes in asset management for individuals in the academic, research and medical fields, has $410 billion in assets under management and oversees more than 27,000 retirement plans with 3.7 million plan participants.

(Reporting by Lauren Keiper, editing by Ros Krasny, Dan Grebler and Andrew Hay)