Based on a article in remodeling magazine (yeah I have never heard of it either so take the numbers below as an article of faith):
- Minor Kitchen Remodel 88% (ROI) $8,655 (Avg Cost)*
- Second-Story Addition 83% (ROI) $73,553 (Avg Cost)
- Bathroom Remodel 81% (ROI) $9,135 (Avg Cost)
- Bathroom Addition 81% (ROI) $13,918 (Avg Cost)
- Family Room Addition 75% (ROI) $30,960 (Avg Cost)
- Major Kitchen Remodel 71% (ROI) $31,090 (Avg Cost)
- Deck 55% (ROI) $8,022 (Avg Cost)
Link to source here.