According to this site, average health insurance cost for family coverage is almost $20K/y - http://www.ncsl.org/research/health/health-insurance-premium...
So it really depends on whether your employees are all single.
Also I think you're not counting other things that are normally counted in overheard: cost for space, recruiting, etc: http://web.mit.edu/e-club/hadzima/how-much-does-an-employee-...