Fertility (TFR) and life expectancy (e0) decline across the demographic transition, and the old age dependency ratios (OADRs) that they generate rise. The bright
colored lines show historical data, starting with an open circle at the first available year and ending in 2010 with a closed
colored circle. The faded lines show projected trajectories. The purple line for Europe represents the earlier experience
of the more developed countries (MDCs; red line). The green line for India represents the earlier experience of less developed
countries (LDCs; blue line). The gray contour lines show the combinations of fertility and mortality for which the OADR is
constant in a steadystate (stable) population. Historical data from 1950 to 2010 and forecasts from 2010 to 2100 are from
the UN (5). Prior to 1950, data for India are taken from (31). Data for Europe prior to 1950 are based on estimates in tables 6.2 to 6.5 in (32) for the period 1800 to 1900, and (33) for the period 1900 to 1950. The OADR contours are derived from (34) using the Model West Female life table with a mean age of childbearing at 29.