2012 auto preview: New car bonanza

Manufacturers around the world have learned that gaining -- or even holding -- market share is largely dependent on how often they turn over their fleets, and they have taken the lesson to heart.

According to John Murphy of Bank of America Merrill Lynch, author of the widely followed annual "Car Wars" study, the industry replaced 16% of its fleets annually between 1991-2011. But the replacement rate jumps to 23% for the 2012 model year, which began Oct. 1, and then surges to an extraordinary 32% for the following year.

While customers got to choose among an average of 38 new models every year for the past two decades, they will see some 46 new offerings coming their way every year for the next four.

All new models aren't created equal, of course, and some automakers are moving faster than others. Herewith, an analysis of the activity by each automaker with a guide to its hottest models.

NEXT: General Motors