CREATE TABLE table_79687 ("Call sign" TEXT, "Frequency MHz" FLOAT, "City of license" TEXT, "ERP W" FLOAT, "Class" TEXT, "FCC info" TEXT)

What is the average frequency mhz of the loomis, south dakota city license?
SELECT AVG("Frequency MHz") FROM table_79687 WHERE "City of license" = 'loomis, south dakota'
SELECT AVG("Frequency MHz") FROM "table_79687" WHERE "City of license" = 'loomis, south dakota'