All done

Here is a link to a study done in 1994 regarding this issue, by FSANZ - it is long, but an interesting read. One thing that stood out was the "majority" of parents in the NZ study, began solids at 4mths, whereas only a quarter of study participants in Australia did with the remaining number waiting until at least 5mths. It went on to say that the NZ participants were much more educated in the physiological readiness of their babies than Australian participants were.
Worth a read if you have time.