You're right guys, I think I multiplied the five employees twice in my calculation.

Let's take, suedaninvestments example,

$33,000 per year more in wages for five full-time employees.  Let's assume wages will eventually have to go up by 25% over the next 2-3 years to hit $15.  That means current labour costs are $132,000 ($33000/0.25)
If labour costs are currently running at 10% -12% of revenue, that is say $1,300,000 of revenues per employee.  Wage increase of $33,000/$1,300,000 means my revenue has to go up by 2.5% to cover the extra cost. 

For restaurants, that top line revenue number will have to go up by around 7%. 

However, point to be made is that everyone's cost goes up, not just yours.  If you are running a good business, you can justify that price increase because everyone will be in that boat and will have to do the same.  If you have to eat that yourself as an owner, you don't have a feasible business, sorry.