Million-dollar sales, mostly in Edgartown and Chilmark, are dominating the Island’s real estate market, as figures from the Martha’s Vineyard Land Bank make abundantly clear.

Hard numbers illustrating the trend underscore urgent concerns about the lack of affordable housing, the subject of a standing-room-only forum last weekend.

A rising tide lifts all boats, and the evolution of million-dollar price tags from shocking rarities to barely remarked commonplaces has ratcheted up the cost of even the most basic shelter.