human
Considering the provided database schema and associated query, produce SQL code to retrieve the answer to the query. 
###Database Schema: Rank, County, Population (1960), Population (2000), Population (2040)
###Question: What was Oslo's population in 1960, with a population of 507,467 in 2000?
gpt
SELECT AVG Population (1960) FROM table WHERE County = oslo AND Population (2000) > 507,467