Why not percentages?

The Winston-Salem Journal newspaper recently printed charts that show that more blacks than whites have been executed in North Carolina. Every time I see such a chart it compares the total executions for each race, or compares the percentage of executions for each race to the total population of each race. Why do they never compare the total executions to the number of convicted criminals who were eligible for the death penalty for each racial group. Could it be because the numbers would not support their cause. What I want to see is a chart that compares the number of executions to the number of capital offense convictions for each race, or a chart that show the percentage of capital crimes commited by each race compared to each races percentage of the population.