As do GUE.
I have no idea of the numbers either...
I only responded to your post that I originally quoted as you stated 90%-99%, which now you say you have no idea about the numbers.
Since SSI is one of the larger agencies I will assume more and more divers are becoming familiar with primary donate. Notice I don't say long hose, necklaced secondary or anything about configuration. I just say SSI teaches primary donate.
If you watch the SSI training videos you will see primary donation using what many consider standard gear configuration: Jacket BCD, Primary 2nd stage on a normal length hose coming over the right shoulder, and an octopus secondary stored under the right arm near the chest.