Neighborhood Change Database (NCDB) gives users instant access to US Census data from 1970, 1980, 1990, 2000, and 2010 at the census tract level. The All years normalized to 2010 selection allows you to compare data for various years. The data for years 1970, 1980, 1990, and 2000 are recalculated and normalized, and the report uses the 2010 tract ID (FIPS code). This allows you to compare data for various years within the exact same boundary definitions. By selecting “All years normalized to 2010” you can do actual apples-to-apples comparisons of historic data in 2010 tract definitions.