old census forms etc

SO ...

I looked on the actual census forms.

There are copies of all of them ....

And .... the question was:

1950 yes

1960 NO

1970 yes

1980 short form - NO

1980 long form - yes

1990 yes

2000 short form - NO

2000 long form - YES

2010 NO

and the question boiled down to

are you a citizen

naturalized

legal

AP

or NO not a citizen ...

data here

https://www.census.gov/history/www/through_the_decades/questionnaires/1990_1.html