The citys most populous ethnic group, non-Hispanic Whites, have proportionally declined from 72.1% of the population in 1990 to 47.9% in 2010, even as total numbers of all ethnicities have increased with the population. Hispanics or Latinos of any race make up 31.5% of the population. Of those 24.0% are of Mexican, 1.4% of Salvadoran, 0.9% of Puerto Rican, 0.9% of Cuban, 0.6% of Guatemalan, 0.2% of Peruvian, 0.2% of Colombian, 0.2% of Honduran and 0.2% of Nicaraguan descent.
Question: How many percent has the population of non-Hispanic whites declined in the 10 years after 1990?
Answer: 24.2