THE golden years of retirement, when decades of toil are traded for some downtime, are starting later. In the mid-1980s, 25% of American men aged 65-69 worked; today, nearly 40% do. The situation is the same for younger men. In 1994, 53% of 60- to 64-year-olds worked; now 63% do. American women are working longer too, and similar upticks have been witnessed in Japan and other parts of western Europe. Since unhealthy workers tend to retire earlier, many attribute the ageing workforce of today to improvements in health. Mortality rates for American men in their 60s have declined by 40% since 1980; for women, they have fallen by 30%. Education and occupation are also relevant. In countries of the OECD, the share of 55- to 64-year-olds with a college education has increased in the past three decades, and better-educated people tend to work longer, doing white-collar jobs. In a similar vein, the fact that modern jobs in general are less physically taxing than those of yore allows all people to work for longer or look for jobs suitable to their advancing years.

But these are not the primary drivers of the greying workforce, suggests Courtney Coile, an economist at Wellesley College. Social-security reforms and other institutional changes play a central role. In recent decades, many countries and companies have altered the way they fund pensions. About half of Americans working in the private sector participate in employer-sponsored plans. In the 1980s a third of these were “defined benefit” (DB) schemes, under which a company pays its retired employee a predetermined lump sum depending on tenure, age and past earnings. Now, though, “defined contribution” (DC) plans, for which employees contribute a percentage of their paycheques to their retirement fund, have largely supplanted DB plans. These are generally lower than DB pensions (hence their popularity with employers), so their recipients cannot afford to retire so early. By working longer, they increase the size of the pot. Researchers reckon the growth in DC plans has led to a five-month increase in the median retirement age.

Reductions in the generosity of social security and disability insurance have also had an impact. Since the 1990s, Italy, Germany, Japan and others have raised the minimum age at which citizens can accept retirement benefits. The labour-force participation rates for older workers there have risen in lock-step, with a one- to two-year lag. A final factor is the increased number of women in the workforce: about 44% more hold a job now, across 12 developed countries, than in 1995. And, like men, they are working longer. Given that married couples often retire at the same time, this “co-ordination”, which sees men working longer to keep up with Stakhanovite wives, can have profound effects. In Canada, for example, it could explain around half the change in the labour-force participation rates of married men aged 55-64.

This is good news. The “lump of labour” fallacy holds that older workers threaten economic prosperity by crowding out younger workers. (The same argument had been used to exclude women from the workforce.) In fact the economies of many countries with ageing workforces are growing quite quickly. Older workers use their wages to buy goods and services made by other workers. And as Lisa Laun of Sweden’s Institute for Evaluation of Labour Market and Education Policy points out, with more workers, of whatever age, tax revenues and pension contributions rise. That means a larger pie for everyone.