Reconstruction played out against an economy in ruin. The Confederacy in 1861 had 297 towns and cities with a total population of 835,000 people; of these 162 with 681,000 people were at one point occupied by Union forces. Eleven were destroyed or severely damaged by war action, including Atlanta (with an 1860 population of 9,600), Charleston, Columbia, and Richmond (with prewar populations of 40,500, 8,100, and 37,900, respectively); the eleven contained 115,900 people in the 1860 census, or 14% of the urban South. The number of people who lived in the destroyed towns represented just over 1% of the Confederacys combined urban and rural populations. The rate of damage in smaller towns was much lower—only 45 courthouses were burned out of a total of 830.

Based on the above article, answer a question. How many more people lived in prewar Atlanta than Columbia?
1500