HMC, I believe it is true, yes: Eastern Europe and Scandanavia are the areas I was thinking of, but I think there's a lot of individual variation.
I couldn't find anything pinning it down on Google, but I did find this:
"There is no compelling reason to begin school at age five, according to an early years review commissioned by the Scottish Executive, David Henderson writes.
After analysing start dates around the world, Christine Stephen of Stirling University concludes that there is no right age for launching into a formal school career. Even starting at seven does not disadvantage children, Dr Stephen states in the latest Insight publication on early years education.
Six or seven is the average age for starting, one international review points out, but Northern Ireland has recently moved to four, as has the Netherlands as part of its early intervention strategy"