Fig. 7.

Empirical histograms for the two exponents ${\beta }_1$ and ${\beta }_2$ that describe the two regimes of type-2 cities. (Top) Histogram for ${\beta }_1$. The average is ${\overline{\beta }}_1\approx 5.35$ and the dispersion is $\sigma \approx 3.31$. (Bottom) Histogram for ${\beta }_2$. The average is here ${\overline{\beta }}_2\approx 1.32$ with a dispersion $\sigma \approx 0.81$. For most cities we have ${\beta }_1>{\beta }_2$.