The given line graph shows data about birth rates in the UK in 6 age groups: under 20; 20-25; 25-28; 30-35; 35-39; 40 and over; between 1973 and 2008.
Overall, it can be seen that nearly all figures experienced gradual changes without sharp movements. As regards the age group 25-29, it notably fluctuated over the period in the question, finally having reached its lowest level of 120 at the end. Despite that, it is a peak level among all figures.
Looking at the details, the figure of people of 40 and over years old are the most unchanged among the other groups, as it shows a downward trend from 20 to 10, with only 10 births in comparison. Age groups under 20 and 20-25 go to the same up direction, with the former declined from 125 to 50, and the latter from 60 to 40.
By contrast, the three other groups demonstrate an upward trend, with 30-35 group reaching stability during 1983-1998 at 80, then marginally grew to 85. Meanwhile, 35-39 soared between 1988 and 1998, after which, for the final ten-years remained stable.