The annual number of marriages in Japan exceeded one million couples in the early 1970s, which, coupled with the marriage rate (per 1,000 population) hovering over 10.0, showed an apparent marriage boom. However, both the number of couples and the marriage rate started declining thereafter. They rose again in the late 1980s, but in recent years, they have been on a declining trend in general. In 2011, 662,000 couples married, marking the first time this number fell below 700,000 couples. In 2015, 635,000 couples married, and the marriage rate was 5.1.
The mean age of first marriage was 31.1 for men and 29.4 for women in 2015, a rise by 2.6 years and 3.1 years, respectively, over the past twenty years (in 1995: grooms, 28.5; brides, 26.3). The declining marriage rate and rising marrying age in recent years as described above is one explanation for the dropping birth rate.
In contrast, divorces have shown an upward trend since the late 1960s, hitting a peak of 290,000 couples in 2002. Subsequently, both the number of divorces and the divorce rate have been declining since 2003. In 2015, the number of divorces totalled 226,000 couples, and the divorce rate (per 1,000 population) was 1.80.
http://www.stat.go.jp/english/data/handbook/c0117.htm
http://www.stat.go.jp/english/data/handbook/pdf/2016all.pdf#page=23
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