Delayed Marriage, Declining Fertility
A book chapter by Francesco Billari says,
In 1980, in most countries [the report is on Europe], first marriage was experienced on average before age 25 for women: only a few exceptions existed. This pattern completely changed in the next 20 years: by 2000, in only a small minority of countries is the mean age at first marriage lower than 25.
…In 1980, only a few cases of ‘low’ [between 1.3 and 1.5 children per woman] fertility levels were recorded (for the former Federal Republic of Germany, Luxembourg and San Marino). By 2000, 11 countries have ‘lowest low’ fertility [below 1.5 children per woman] and 11 have ‘very low’ (but not lowest low fertility). At the beginning of the new millennium, very low fertility is pervading the UNECE area, and lowest low fertility is present in a substantial group of countries. In fact, very few countries, which belong to quite different regions, have fertility above two children per woman (Iceland, Israel, Kyrgyzistan, Turkey, the United States and Uzbekistan).
The population halving time for a country with a fertility rate of 1.5 is 65 years. For a fertility rate of 1.3, the halving time is 32 years.
The table of contents for the full book can be found here.