In recent years, Nanjing has been developing its economy, commerce, industry, as well as city construction. In 2013 the citys GDP was RMB 801 billion (3rd in Jiangsu), and GDP per capita(current price) was RMB 98,174(US$16041), a 11 percent increase from 2012. The average urban residents disposable income was RMB 36,200, while the average rural residents net income was RMB 14,513. The registered urban unemployment rate was 3.02 percent, lower than the national average (4.3 percent). Nanjings Gross Domestic Product ranked 12th in 2013 in China, and its overall competence ranked 6th in mainland and 8th including Taiwan and Hong Kong in 2009.
Question: How many dollars higher was the average urban disposable income over the average rural disposable income?
Answer: 21687