In 1777, U.S. leaders voted to permit fireworks displays, and in 2011, Americans used more than 200 million pounds of fireworks on the Fourth of July.

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he Fourth of July wasn't always dominated by burgers on the grill and explosions in the sky, though the colorful celebrations we enjoy today were forecasted by at least one founding father. On July 3, 1776, the day before the Continental Congress formally adopted the Declaration of Independence, John Adams wrote a letter to his wife saying the historic day should be celebrated with "pomp and parade… bonfires and illuminations… from one end of the continent to the other." Here, a look back at the numbers behind that fateful July in 1776, and July 4 as we celebrate it today:

56 
Men who signed the Declaration of Independence in the summer of 1776, after America's second Continental Congress voted to secede from England

5 
Inches taken up by John Hancock's famously enormous signature on the 24-1/4-inch by 29-3/4-inch piece of parchment

1
Signed copies of the original Declaration of Independence, which was engrossed on parchment, kept at the National Archives building in Washington, D.C.

26 
Paper copies of the Declaration of Independence produced in 1776 that are still in existence

21 
Copies owned by American institutions 

2
Copies owned by British institutions

3 
Copies in the possession of private owners 

$8.1 million 
Price that one copy sold for in a 2000 auction

2.5 million
People who lived in newly independent America in July 1776

313 million
People who live in America today

1777
Year that Congress first authorized fireworks displays to commemorate the fledgling country's anniversary, initiating a national tradition  

$649 million 
Amount Americans spent on fireworks in all of 2011 

90 
Percent of total American fireworks sales that go toward the Fourth of July

212.1 million
Weight, in pounds, of those Fourth of July fireworks

14,000+
Fireworks displays that light up U.S. skies each Fourth of July 

60 million 
Americans who display the flag on the Fourth of July

$301.5 million
U.S. flag manufacturers' total sales in 2009

$3 million
Sales of U.S. flags imported from China

64
Percent of Americans who participate in cookouts on the Fourth of July

150 million 
Hot dogs consumed on the Fourth of July

$61.16 
Amount the average adult spends on a Fourth of July cookout 

52.7 million
Cases of beer sold to Americans in the two weeks leading up to the Fourth 

51
Percent of deadly traffic crashes on the Fourth of July that are related to alcohol

Sources: Bloomberg, History.com, National Geographic, Star Exponent, U.S. Census, U.S. National Archives