Folks,
The biggest jump (by percentage increase) is from 0.5 to 1.5 (duh, no antlers to 50 or 60 inches of antler). The next biggest jump is from 1.5 to 2.5. The next is 2.5 to 3.5, followed by 3.5 to 4.5, followed by 4.5 to 5.5. At age 5.5, antler size plateaus on average and a 6.5 or 7.5 is likely very similar to what he was at 5.5.
Mick