(AP Photo/Daytona Beach News-Journal, David Massey)

The Fourth of July is the official summer holiday–the barbecues, fireworks and pool parties are American staples.

We know that in 1776, our Founding Fathers signed the Declaration of Independence, making July 4 America’s birthday. Today our country turns 235-years-old.

In honor of July 4, here are ten facts about the holiday–and our country–that may surprise you, courtesy of the U.S. Census Bureau.

1. 81 million Americans said they took part in a barbecue in 2010.
2. In 2007, U.S. manufacturers’ shipments of fireworks and pyrotechnics (including flares, igniters, etc.) valued at $231.8 million.
3. Our country’s patriotism is apparent by our towns and cities’ names. Thirty-five places have “eagle” in their names; 31 places have “liberty” in their names; 11 places have “independence” in their names; nine places have “freedom” in their names; five places have “American” in their names and one place has “patriot” in its name.
4. When the Declaration of Independence was signed in 1776, an estimated 2.5 million people lived in the new nation. Today the country’s estimated population is 311.7 million.
5. Remember how much we hated the British back then? We’ve made up nicely. Last year $98.3 billion of trade took place between the United States and the United Kingdom, making them our sixth-leading trading partner.
6. $486,026 worth of U.S. flags exported in 2010. The leading customer? Mexico, our neighbors to the south, bought $256,407 worth.
7. The odds that your baked beans side dish originated from North Dakota is over one in three. The state produced 36 percent of the nation’s dry, edible beans in 2010.
8. The surname of our first president, George Washington, ranked 138 for frequency among all last names tabulated in the 2000 Census. Other early presidential last names that appeared on the list, along with their ranking, were Adams (39), Jefferson (594), Madison (1,209) and Monroe (567).
9. The is a more than one in four chance that the hot dogs and pork sausages enjoyed on the Fourth of July are from Iowa. As of March 1, 2011, the state was home to 19.0 million hogs and pigs–more than one-fourth of the nation’s estimated total.
10. There are six states where the value of broiler chicken production was $1 billion or greater between December 2009 and November 2010. These states were Georgia, Arkansas, North Carolina, Alabama, Mississippi and Texas.

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