"Yearlings" can vary greatly in size depending upon multiple factors such as actual hatch date (March versus September for example), size at hatching (6 grams versus 12 grams), feeding frequency (every 5 days versus every 7 days or even longer), size of the meals fed, temporary setbacks such as a regurge, individual genetic growth rate (some are naturally late bloomers), efficiency at digestion/utilization of meals, etc.
I have 2010 hatchlings, my own as well as those produced by others, that range in weights from 16 grams to 92 grams and I've seen larger yearlings.