CREATE TABLE table_24674 ("State Rank by Revenue" FLOAT, "Company Name" TEXT, "National Rank" FLOAT, "Revenue  ( $billions )  2012 estimate" TEXT, "Headquarters City" TEXT, "Known for" TEXT)

What is the national rank of Windstream?
SELECT MIN("National Rank") FROM table_24674 WHERE "Company Name" = 'Windstream'
SELECT MIN("National Rank") FROM "table_24674" WHERE "Company Name" = 'Windstream'