I don't disagree with what you're saying, but the math you used to reach that is none less pervasive than using 1 out of statements. You also can't simply choose to ignore the changing number of your population. For simplicity's sake lets say there are 100 Asian people. 20 of them commit a crime. So you say 20% of Asian people are criminals. 64 of those Asian people die. Of the remaining 46, 20 of them are criminals, making for roughly 43%. Well now more Asian people are born and more of them die for a net change of +5 people. So now there is 69 people, but of those 20 that were criminals, 11 of them died while only only 2 more people were classified as criminals for a total of 11 criminals out of 69 people. Or, 22 criminals out of (at minimum) 116 people so that would make roughly 17% criminals.