My understanding is that, in the 2016 census, there were almost 4,000 people who had self-identified as stateless, but this refers only to people who have self-identified. Without a full, broad study, it's unclear how many stateless persons there are in Canada. Obviously, people who are stateless may not want to become identifiable to the government for fear of becoming removable when they come to the attention of the government.
It's really unclear and I think the government has an opportunity to use its resources to track and identify stateless persons and provide some pathways for them.