CREATE TABLE table_28450 ("Year" FLOAT, "Starts" FLOAT, "Wins" FLOAT, "Top 5" FLOAT, "Top 10" FLOAT, "Poles" FLOAT, "Avg. Start" TEXT, "Avg. Finish" TEXT, "Winnings" TEXT, "Position" TEXT, "Team ( s ) " TEXT)

How many different starts had an average finish of 17.9?
SELECT COUNT("Starts") FROM table_28450 WHERE "Avg. Finish" = '17.9'
SELECT COUNT("Starts") FROM "table_28450" WHERE "Avg. Finish" = '17.9'