The Canada health transfer and the Canada social transfer were both created in fiscal year 2004-05 out of the split of what was then the Canada health and social transfer. It was a combined transfer for all health and social purposes. In 2004-05 it was split to increase the transparency of what the government was supporting through health and through social. It made it clear. And then we could do the notional allocations and the CST.
On November 17th, 2014. See this statement in context.