Any county not listed for this state is $37 unless otherwise indicated.
 
1800 Census
Delaware - $97  for the entire state

1810 Census 
Delaware - $97 for the entire state

1820 Census
Delaware - $97  for the entire state

1830 Census 
Delaware - $57 each for the counties of New Castle, Kent
           $97  for Sussex Cty. 

1840 Census 
Delaware - $57 each for the counties of Kent or New Castle
           $97 for the county of Sussex

1850 Census 
Delaware - $97 for Kent or Sussex 
          $147 for New Castle 
           $57 for entire 'slave' schedule 

1860 Census 
Delaware - $97 each for the City of Wilmington (separate from the
                    county census), Kent Cty, Sussex  Cty.
          $147 for New Castle Cty.
           $27 each county for 'slave' schedules

1870 Census 
Delaware - $197 each for the counties of Kent, New Castle (excluding 
                    the city of Wilmington), Sussex
     City of Wilmington - $97

1880 Census 
Delaware -  $97 for the county of Sussex  
           $197 each for the counties of Kent       
           $247 each for the counties of New Castle
        OR  $22 each Enumeration District (EDs) 
  
1900 Census 
Delaware - $57 for the county of Sussex 
          $147 for the county of Kent
          $197 for the county of New Castle

1910 Census
Delaware - $97 each for the counties of Kent, Sussex 
          $197 for the county of New Castle

1920 Census 
Delaware - $57 for the county of Kent 
           $97 for the county of Sussex 
          $347 for the county of New Castle 
   City of Wilmington - $247
   (use "Comments" to get info on reducing cost of populous areas)