Dallas Morning News Pamela Yip Many experts say one of the best ways to build wealth is to get married and stay married. In fact, those who marry "till death do us part" end up, on average, four times as rich as those who never marry, according to Barbara Dafoe Whitehead and David Popenoe, who run the National Marriage Project at Rutgers University. This is partly because marriage provides economies of scale - two people sharing expenses. If both spouses are working, you also have two incomes sustaining the household. It's when an elderly spouse dies that the financial equilibrium can be thrown off. If the husband dies, it's all that much more devastating to the wife. Despite general declines in old-age poverty rates, nearly 30 percent of older non-married women are either poor or near poor, according to a recent report by the Center for Retirement Research at Boston College. "Of all the factors associated with poverty in old age, the most critical is to be a woman without a husband," the center said. Take a look at these sobering statistics compiled by Nadia Karamcheva, a graduate student in economics at Boston College, and Alicia H. Munnell, director of the retirement research center:

• "17.4 percent of single women older than 65 fell below the poverty line in 2004.
• "An additional 10.8 percent were classified as "near poor," which means that their income was less than 125 percent of the poverty threshold.
• "As a whole, 28.2 percent of single older women are either poor or near poor - a clearly vulnerable group.

Not only do single women have high poverty rates, they also constitute a significant portion of the elderly population, a share that steadily increases with age. Among those age 80 or older, non-married women account for 56 percent of the population. The study didn't look at women who have never married. "Women who enter retirement non-married tend to end up poor, because the U.S. retirement income system bases benefits on earnings, and women have lower lifetime earnings than men," Ms. Karamcheva and Ms. Munnell wrote. "They earn lower wages, are more likely to work part time, and spend fewer years in the labor force, taking time off to have children or take care of family members. As a result, these lower lifetime earnings produce lower Social Security and pension benefits." Those women, especially those who are older, face a harsh reality, said Laurie Young, executive director of the Older Women's League. "The reality is that even though many more women work outside of the home, they often work in entry-level or service-type jobs where they earn less than $30,000 a year. The caregiving responsibilities eat away at their ability to get into jobs where they're likely to have some kind of pension." When their husbands die, widows experience a drop in income because of lower Social Security and pension benefits obtained through their husband's employer, the retirement research center report said. "When the husband dies, the couple's Social Security benefit is cut by between one-third and one-half," the report said. "The couple's private pension benefit either disappears completely or is reduced." That's because many couples don't select "joint-and-survivor annuity" payments for pension benefits, which provide continued benefit payments to a surviving spouse. "Once you're knocked down financially after you become a widow, you never rebound from that," Ms. Munnell said in an interview. "The corollary is, you don't bounce back, you stay at this level, and the significant point is that these couples who are widowed early are in worse shape to begin with. They tend to be low-income. The husband tends to be sick for a long period before he dies. Both of those situations affect your financial well-being." Because the husband's illness has prevented him from working, his illness eats up the family's assets, she said. What's more, before widowhood these couples had lower incomes because of lower levels of education, Ms. Munnell said. "In short, women who are most likely to be struggling after widowhood are also the ones who are most likely to have been in a relatively poor economic situation even before widowhood," Ms. Munnell and Ms. Karamcheva wrote. Ms. Munnell and Ms. Young said women should get a job that provides retirement benefits and stay in the workforce as long as possible. "It really means start saving for retirement when you're in your 20s, when you start your first job," Ms. Young said.