We compute the cumulative wage share at each percentile of the wage distribution, and we plot the relationship between cumulative wage shares (on the vertical axis) and percentiles. In a typical sample, What does the plot of cumulative wage shares against percentiles look like?
1) A straight line with a positive slope
2) A straight line with a negative slope
3) A curved line that is concave upwards
4) A curved line that is concave downwards