You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Race_and_ethnicity_in_the_United_States_Census

Context:
Race was asked differently in the Census 2000 in several other ways than previously. Most significantly, respondents were given the option of selecting one or more race categories to indicate racial identities. Data show that nearly seven million Americans identified as members of two or more races. Because of these changes, the Census 2000 data on race are not directly comparable with data from the 1990 census or earlier censuses. Use of caution is therefore recommended when interpreting changes in the racial composition of the US population over time.

Question:
In what year were census respondents first able to select more than one race? 

2000