In Baltimore, white people make up 28 percent of the population but 50 percent of the city's police officers. In Philadelphia, where police and protesters clashed last Thursday during a #FreddieGray rally, whites are 37 percent of the population but 58 percent of the police force. In Sacramento, whites comprise just 36 percent of residents but 72 percent of police. Those are just a few of the departments whose ethnic makeup is dramatically out of sync with the demographics of the cities they serve.