Attitudes toward marriage have changed substantially since World War II. Most obvious was the declining marriage rate, which dropped from 8.5 marriages per 1,000 Finns in 1950 to 5.8, in 1984, a decline great enough to mean a drop also in absolute numbers. In 1950 there were 34,000 marriages, while in 1984 only 28,500 were registered, despite a growth in population of 800,000. An explanation for the decline was that there was an unprecedented number of unmarried couples. Since the late 1960s, the practice of cohabitation had become increasingly common, so much so that by the late 1970s most marriages in urban areas grew out of what Finns called "open unions." In the 1980s, it was estimated that about 8 percent of couples who lived together, approximately 200,000 people, did so without benefit of marriage. Partners of such unions usually married because of the arrival of offspring or the acquisition of property. A result of the frequency of cohabitation was that marriages were postponed, and the average age for marriage, which had been falling, began to rise in the 1970s. By 1982 the average marriage age was 24.8 years for women and 26.8 years for men, several years higher for both sexes than had been true a decade earlier.. By how many years did the marriage age for women and men differ in 1982?