The distribution of heights of both five-year old boys and seven-year old boys is approximately Normal. The mean height of a five-year old boy is 43 inches and the standard deviation is 1.8 inches. The mean height of a seven-year old boy is 48 inches and the standard deviation is 2.1 inches. John's height was 44 inches on his fifth birthday, and today, on his seventh birthday, he measures 49 inches tall. What can you conclude about the rate of John's growth when compared to other boys his age?