Individual states in the U.S. occasionally hold their own censuses.  Iowa had a census in 1915 and another in 1925, in which each individual's information was noted on a separate index card. 

Polk County, Iowa

Card #P50 Andrew Tinlin

Female [sic], white, married, can read and write, is naturalized.  Years in U.S. - 10, years in Iowa - 8.  Age 22.  Living at 834 5th Street, Des Moines, Ward 4.  Occup. - Mine fireman.  Unemployed for 4 months in 1914.  Total 1914 earnings - $720.  Extent of education - Common School, 8 years.  Born Scotland.  Church - Presbyterian.  Parents born in Scotland.

Card #P51 Grace Tinlin

Female, white, married, can read and write.  Years in Iowa - 12.  Age 20.  Living at 834 5th Street, Des Moines, Ward 4.  Occup. - Housewife.  Extent of education - Common School - 8 years, High School - 1 year.  Born Iowa.  Church - Methodist.  Father born Illinois.  Mother born Iowa.

There were no other Tinlins listed in Polk County.

There were no Tinlins listed in Greene County.

1925 Iowa State Census

There were no Tinlins listed in Polk County.