On our property, we typically see the biggest jump from 2.5 to 3.5. After that, it slows down some. I never really thought about the % increase from year to year.

Most of this increase really depends on food quality and genetics. I also read somewhere that winter harshness may contribute to the following year's antler growth. The article stated that the period right after a deer drops his antlers is very critical for the following years growth. This is because he's trying to recover from the rut and any food he eats goes directly to staying alive, rather than replenishing and supporting future antler growth. Makes sense to me.