If unknown, this is the country of residence identified in the inventor's patent filings. Active: The first and last year in which an inventor received a patent issuance, except when activity was prior to digital records, in which case year of birth (b) and death (d) may be substituted. If an inventor's first year is 1976 or a few years after, there may be activity prior to this; earlier dates are not present in the primary source, and would require a secondary source.