Remember that Statista is an aggregator and not the original source of the data. Make sure not to put Statista in the author position in your citation. Here are some examples:
US Census Bureau. (n.d.). Resident population of Washington in 2016, by race and ethnicity. In Statista - The Statistics Portal. Retrieved September 14, 2018, from https://www.statista.com/statistics/306071/washington-population-ethnicity-race/.
US Census Bureau. "Resident Population of Washington in 2016, by Race and Ethnicity." Statista - The Statistics Portal, Statista, https://www.statista.com/statistics/306071/washington-population-ethnicity-race/, Accessed 14 Sep 2018