By taking antilogs, we can use the model to predict the TFRm for a certain country as
When SR20-39 > 1, there are more men than women aged 20-39, and the number of men in the denominator becomes even larger, reducing the TFRm even further.
Take the natural logarithm of 2STFR in expression (5) and substitute ln(TFRm) by expression (7) to find
To be more precise, once we assume that TFRw * [lw.sub.[mu]] [approximately equal to] TFRm * [Lm.sub.[mu]], expression (13) follows from expression (6), together with the traditional approximation NRR [approximately equal to] [k.sub.g] x TFRw x [lw.sub.[mu]].
The gap between TFRw and TFRm rises from 0.2 in 1990-1995 to 0.4 by 2050.