CREATE TABLE table_51323 ("Episode" TEXT, "Air Date" TEXT, "Timeslot  ( EST ) " TEXT, "Season" FLOAT, "Rating" FLOAT, "Share" FLOAT, "18\\u201349" FLOAT, "Viewers  ( m ) " FLOAT, "Rank  ( # ) " TEXT)

What is the total number of ratings among the 18 to 49 group that was aired on January 7, 2009?
SELECT COUNT("18\u201349") FROM table_51323 WHERE "Air Date" = 'january 7, 2009'
SELECT COUNT("18\u201349") FROM "table_51323" WHERE "Air Date" = 'january 7, 2009'