American keeps lowering the price that they will sell miles for. After the merger with US Airways they took the Dividend Miles approach of putting miles on sale three fourths of the year. The only purpose that ‘regular price’ serves is to be a reference point that allows them to announce a huge (always on) sale.
At first they hovered a little over 2 cents a mile, then the price point fell to 2 and then below 2 cents. Each promotion would vary a bit but the trend has been downward.