most, if not all, of the growth in employment comes from the 300,000 high-impact firms in the economy over any four-year period. Depending on the time period studied, this is about evenly split between firms with fewer than 500 employees (the SBA definition of small business) and firms with more than 500 employees. Therefore, it would appear that both small and large firms contribute about equally to employment growth.

Ruth Marcus - The little engine that can’t - The myth about small businesses and jobs