20 years (down 497) 35 -- 39 years (down 468) 20 -- 24 years (down 441) 30 -- 34 years (down 333). Age-specific fertility rates measure the number of live births 1,000 women in a particular age group have in a given period (usually a year). Women aged 30 -- 34 years had the highest fertility rate (122 births per 1,000 women aged 30 -- 34 years) in 2012. The 2012 rate suggests that for every 1,000 women aged 30 -- 34 years, there were nearly four fewer births than in 2011. The rate for women aged 25 -- 29 years (103 per 1,000) also dropped, by nearly five births per 1,000. Compared with the high fertility seen in the early 1960s, women in all age groups now have fewer babies. In 1962, women aged 20 -- 24 years had the highest fertility rate (265 per 1,000), followed by those aged 25 -- 29 years (259 per 1,000), and 30 -- 34 years (152 per 1,000). Total fertility rate lower The total fertility rate summarises the age-specific fertility rates into a single-number indicator of fertility. It indicates, on average, the number of babies a woman would have in her lifetime if the age-specific fertility rates in a given period stayed the same throughout her life. The total fertility rate for the March 2012 year was 2.04 births per woman --  down from 2.12 births in 2011. Annual fluctuations in the total fertility rate do not necessarily indicate changes in family