We've asked Census for some historical background on when the word has been used in the past. We'll update with that information.
Meanwhile, a question for the group:
We'll keep the question open for 48 hours.
Update at 1:10 p.m. ET: We've posted another update — with an image from the 2000 Census form — here.
Update at 9:40 a.m. ET: In a statement e-mailed to us this morning, the Census Bureau says that "56,175 respondents" wrote in the word "Negro" on their 2000 Census forms — even though the word was included on the form much as it is on the 2010 Census.
And Census public information officer Robert Crockett tells us that the word "Negro" has been on Census forms since at least 1950.
This year, Census says, the government is going to study the effects of removing the word from the forms.