Thanks Rebel, I obviously didn't spend time searching for what I was looking for.

Previous to this I have used the formula: total savings counting the company match / total gross income. That's not terribly useful I'm finding since we spend less than half of our gross, and a significant part of that is because of taxes. Counting federal, state, local, property, sales, and both sides of payroll taxes we are at over 40% of gross to various taxes. This will certainly go down in retirement except for sales and property taxes.