So far everyone is right. Point of sail, sail inventory, etc. all make a difference. So does the type of the boat. A big, heavy full-keel boat will not the make the same light air speed as a light fin-keel race boat.
ISPA Yachtmaster Offshore Instructor Evaluator
Sail Canada Advanced Cruising Instructor
IYT Yachtmaster Coastal Instructor
ASA 201, 203, 204, 205, 206, 214
As I sail, I praise God, and care not. (Luke Foxe)