Wait .... 550K businesses a month = 6.6M businesses a year. There are 300M _people_ in the US (including children, and others not immediately suited for the entreprenurial life). If each business was started by only one person, that would mean that about 1 out of every 45 people started a business in any given year.
That seems high. May I ask the provenance of the 550K/mo number?