The Term Sailing - a Casual Observation

Over at Google Labs they have developed software that will search through over 5.2 million books: 4% of all books ever published! The Google Labs N-gram Viewer is the first tool of its kind, capable of precisely and rapidly quantifying cultural trends based on massive quantities of data.
So, what better way to test out the N-gram Viewer than to try out the terms "sailing" and "boat" just to see the trend from 1920 to today. The results are pictured below - just interesting to note the slow decline of "sailing" while "boat" seems to be making a slight comeback... It is also interesting to graph the phrase "yacht racing". The words did not appear in print together until the late 1860s. "Sailboat racing" did not appear significantly until about 1920. Yacht racing is still out pacing sailboat racing in usage today.

RED LINE = BOAT      BLUE LINE = SAILING