There are about 14,000 homicides per year, or about 38 per day, in the US. If you eliminate just ten cities from that total, it becomes just 30 per day.
Those ten cities are: New York with 333 killings, Chicago 415, Detroit 332, Philadelphia 246, Los Angeles 578, New Orleans 150, Baltimore 234, St Louis 159, Washington DC 104, and Indianapolis 135 means that of the approximately 14,000 murders in the US in 2014, nearly 2700 of them- about 20%- occur in just those ten cities.
These ten cities account for just 8 percent of the US population, but account for 20 percent of the murders.
I have blogged about this before. The problem in this country is not with guns- it is with the culture that prevails in certain densely populated cities. Los Angeles alone is responsible for one out of twenty of the murders in this country. It makes as much sense to say that we could reduce murders in this nation be 5 percent, simply by making it illegal to live in Los Angeles as it does to say that we can reduce murder by making it illegal to own firearms.