I brought this up in another thread, but this is a bit misleading. I don't know about other cities, but for vancouver if they were to use the same measure as they did for edmonton here, it would also be less than half yellow.
The "single family" zone that's in most of the yellow area in Vancouver is comparable to Edmontons, with up to two secondary units allowed on a lot. It's still not enough, but if the mature areas of Edmonton don't count as single family zoning, neither does Vancouvers.
Now, edmonton has made some great strides, and does have some things I wish they would implement in Vancouver (like row houses on corner lots), but we should make sure we're comparing apples to apples