[idlewords]

This is by an antiquated measure. The accepted rate now is 20.6%, first in the nation. Discussion here:

http://www.forbes.com/sites/chuckdevore/2016/09/28/why-does-...

[dragonwriter]

The SPM is not, by any means, the "accepted rate". Whether it's a more appropriate measure for any particular purpose is a legitimate discussion to have.