Question: What was the population as of the 1990 census of the town about which "Sky of Stone" was written?
Sentence (from "Galloway Township, New Jersey"): As of the 2010 United States Census, the township's population was 37,349, reflecting an increase of 6,140 (+19.7%) from the 31,209 counted in the 2000 Census, which had in turn increased by 7,879 (+33.8%) from the 23,330 counted in the 1990 Census; The increase of more than 14,000 in population since the 1990 Census was the 11th-highest in the state.
Relevant evidence: No