How many puppy place books are there?

There are 20 books; Goldie, Snowball, Shadow, Rascal, Buddy, Flash, Scout, Patches, Pugsley, Maggie and Max, Noodle, Princess, Cody, Bear, Honey, Lucky, Jack, Baxter, Sweetie, and Special Edition: Chewy and Chica. There may be more, but i don't know them all.