Source: U.S. Bureau of the Census
Release: Number of Exporters and Known Value for All Countries on a State-by-State Basis
This data series illustrates the movement of exports from the given state to the given country. A missing observation can mean two things. First, missing observations can appear because no exports were made to the listed country that year. Secondly, it could signify a low number of exporters thus giving away proprietary data away.
U.S. Bureau of the Census, Value of Exports to Mexico from South Dakota [SDMEXA052SCEN], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/SDMEXA052SCEN, December 10, 2018.