I believe the 70% stat is from the census, and it would % of households. So it is possible that it reflects a higher % of kids not leaving the nest and renting something, but I also don't think its fully compatible with the narrative that Canadians are being squeezed out of housing (by foreigners) if the home ownership rate is higher than at any other time in history.

Google Statistic Canada data which breaks it down by age group.

Every age group, including the youngest (18-25) have a higher rate of home ownership than 20 years ago.

Those kids will get that house passed down to them.