Source: U.S. Census Bureau  

Release: Annual Estimates of the Population for Counties  

Units:  Thousands of Persons, Not Seasonally Adjusted

Frequency:  Annual

Data for "Resident Population" are estimates as of July 1. Data for 1970, 1980, 1990, and 2000 are annual census.

Population estimates are updated annually using current data on births, deaths, and migration to calculate population change since the most recent decennial census. The annual time series of estimates begins with the most recent decennial census data and extends to the vintage year. Each vintage of estimates includes all years since the most recent decennial census.

Source: U.S. Bureau of Labor Statistics  

Release: State Employment and Unemployment  

Units:  Thousands of Persons, Seasonally Adjusted

Frequency:  Monthly

The Federal Reserve Bank of St. Louis seasonally adjusts this series by using the 'statsmodels' library from Python with default parameter settings. The package uses the U.S. Bureau of the Census X-13ARIMA-SEATS Seasonal Adjustment Program. More information on the 'statsmodels' X-13ARIMA-SEATS package can be found here. More information on X-13ARIMA-SEATS can be found here.

Many series include both seasonally adjusted (SA) and not seasonally adjusted (NSA) data. Occasionally, updates to the data will not include sufficient seasonal factors to trigger a seasonal adjustment. In these cases, the NSA series will be updated normally; but the SA series will also be updated with the NSA data. The NSA series can be located here here.

Some seasonally adjusted series may exhibit negative values because they are created from a seasonal adjustment process regardless of the actual meaning or interpretation of the given indicator.