Simpsons DVD collection upgrade

Here is a list of all the Simpsons DVD's I currently have.

• The Simpsons Christmas with the very first episode of the show plus 1992's "Mr. Plow", 1997's "Miracle on Evergreen Terrace", 1999's "Grift of the Magi", and 2001's "She of Little Faith".
• Seasons 13 (2001-02), 14 (2002-03), and 16 (2004-05); four discs in each box set.

I hope to get more Simpsons on DVD from the complete first 12 seasons (1989-2001), plus season 15 (2003-04) and season 17 (2005-06). In the past, I had the complete first six seasons (1989-95), plus seasons 8-10 (1996-99) and season 20 (2008-09). Soon I'll get seasons 1-12, season 15, and season 17.