single highest =/= majority. it's still roughly 30%, or should be, for most industries. restaurant industry is slightly higher at 35-40%, or should be.
and this isn't some theoretical number either. i am or have been owner/partner in several business, and that's been consistent across all of them.
and in my primary profession, we service around 4500 business clients, of which we are intimately familiar with their financials. it's consistent, at least for the successful ones.
Funny.
In my profession, labor is about 70 percent.
As for restaurants, I was talking mostly fast-food. In sit downs, you have low wages for wait staff due to tipping (I wish that would go away - just pay them and charge more).
If you look at fast food, the numbers come from everywhere.
Food costs are up due to raw packing.
It's up due to shipping - those wages are up (along with the energy required to ship).
Property taxes are up in most places.
Labor costs are up in all places.
And that is why the Big Mac meal will soon be $15.00.
And, who is driving all of these increases??