On the waze.com dashboard and the ticker in the mobile app it is all users in USA & Canada. There is a scoreboard (in the iPhone app at least, should be on other platforms at waze.com eventually) that can further break it down by state and weekly rankings.
The community is still very young, and many of the accounts (unfortunatly probably a majority) are used once and never again by people expecting a TomTom style navigation application right off the bat.
Also keep in mind certain contributions score higher than others. Someone just downloading and starting out in a well established area would earn points slower than someone in a fledgling area where there is more unverified road to munch and cookies to pick up.
Area Manager - Walt Disney World Resort and neighbors
Area Manager - Central Polk County, Florida (Winter Haven, Lakeland, Bartow, Auburndale)