Can't give any firm numbers, but judging from clothes sizes my older 2 were average length babies at birth-3 months old, have been runts since (eg., DD is 3y+8m old & will still be wearing size 2-3yo clothes for another 6 months, I suppose).
DS2 was quite long at birth (even MWs said so), but seems to be about average length now (1yo)... which still makes him seem ruddy enormous compared to his runt siblings.
I know Zebra - it was quite a shock to get him measure a couple of months back and discovered that he was so tall......it was a nightmare carrying both of them - being 'long' at birth babies - I'm only a runt myself and from 30 weeks pg with both pg's had one of their legs permanently jammed until my right ribs!
Centile wise DS1 (stangely the BF one!) stuck to his centile quite rigidly - around the 60th,
But DS2 started off on the 75th and shot up to the 98th..........funnily enough people say that neither of my boys take after me - and their just like their daddy - well they don't say - LOL
Don't know exactly how long he is now, but at 3 months my ds was just off the chart and at 6 months I have had to go out and buy him some new vests for 12 - 18 months . They are really baggy, but he needs them for his length. Mind you, I'm not exactly short.
QoQ aren't boys meant to reach half their adult height by 18mo and girls by 2yo? Or is it 2yo and 2.5yo?
I don't have DD's birth length but she was 62cm at 8 weeks (>98th centile) and off the scale at 4 months (69cm). But at 8yo, she's now settled somewhere round the 75th, where she's been since about 2yo.