Answer:
Average lengh is 29 inches and average weight is 22 lbs. My son was always underweight, and scored around the 10th percentile for weight, but he's 20 months now and has gotten up to the 30th in weight, and length he's 50th.
My son just turned a year old on 6/30. He weighs 24lbs and is 29 inches long. He is in the 90th percentile. He is a big boy, but he's not fat. Doctor said he was fine, just big. Hope this helps.