CREATE TABLE table_71466 ("Episode title" CLOB, "Villain ( s ) " CLOB, "Identity ( ies ) " CLOB, "Reason ( s ) " CLOB, "Original airdate" CLOB, "DVD volume" FLOAT)

How many DVD volumes was identified by Skippy Johnson?
SELECT "DVD volume" FROM table_71466 WHERE "Identity(ies)" = 'skippy johnson'
SELECT "DVD volume" FROM "table_71466" WHERE "Identity(ies)" = 'skippy johnson'