The file mncountycensus.txt contains 6 variables.

The first 5 variables in mncountycensus.txt are from the 1990 census, and the last variable comes from mortality records for the same period.
Each record represents a summary for each of the 87 counties in Minnesota

The variables are
EDUHS - Percent of county with high school education
MEDHHIN - Median household income of the county / $10,000
PERCAPIT - Per capita income of the county / $10,000
PUBWATER - percent of households in county that use public water 
WOOD - percent of households in county that use wood to heat their home

RESPMORT -  log mortality rate due to respiratory disease
in each county.