NEW YORK ( TheStreet) -- The Fourth of July is synonymous with American tradition -- BBQs, fireworks, ice cream, pool parties and the beach. But what could be more American than starting your own business? To be sure, creating a company that will last for a half a century is something that perhaps today's entrepreneurs may not be familiar with, given the current mindset to launch and then sell to the highest bidder -- whether it be a tech giant like Yahoo! ( YHOO) or any number of private equity firms. Private companies generated average annual sales growth of 10% as of May 31, roughly the same growth as a year ago, according to a June report by Sageworks, a private-company financial information firm. Companies also continued to expand their profit margins in this period. Net profit margins rose to 6.6%, up from 4.5% a year earlier, the report says. Sageworks says the estimates are based on financial statements reported by companies in the six months ended May 2013. Service-based businesses, like consulting companies, architecture firms and computer systems-design companies, in particular, are seeing strong growth, the report says. The five businesses featured have figured out how to adapt to changing consumer demands, economic cycles -- including the Great Recession just a few years ago -- increased regulation and the growing digital world to make their businesses have staying power. From an organic egg farm in New Hampshire to a graphics and printing firm on Long Island, these businesses have survived decades worth of changes. We're celebrating Independence Day by highlighting a handful of businesses that have stood the test of time.