Oreos are the most popular cookies in the United States, with Americans scarfing down some 25 billion of the chocolate sandwich confections every year. And since this week marks Oreo's 100th birthday, we thought we'd celebrate with some facts and lore.

To mark the centennial, Kraft is releasing limited-edition Birthday Cake Oreos with sprinkles in the filling, and on the Oreo birthday website, you can send your friends smartphone coupons for free packages of the cookies. (Those will set you back $3.99 a pop, but just think of how popular you'll be!)

Oreos were released in March 1912 and first sold by a grocer in Hoboken. However, its humble beginnings have since been dwarfed by the wide variety of related products that have since hit the market -- Oreo pie crusts, cheesecake and ice cream, to name just a few.

So how do we eat Oreos? Well, that depends. In a research survey by Kraft, the company found that while 84 percent of men eat the cookie whole, women like to savor it a bit more, with 41 percent eating them a little at a time. (Watch a classic Oreo commercial from the '80s below.)

And while we in the US certainly love the cookies, we aren't the only ones -- 362 billion Oreos have been sold in more than 100 countries around the world, but the Oreos you'll find elsewhere aren't always like the ones we enjoy here (for example, Japan has a Green Tea Oreo).

But Kraft did have to make some adjustments to its famous recipe when the treats were released in China in 1996 and sold so poorly that they were almost removed from the country entirely. Market research revealed the Chinese felt the chocolate cookies were too bitter and the white icing in the middle was too sweet, so a few changes were made to accommodate local palates -- and today, Oreos are China's best-selling cookie.

Check photos of some of the many Oreo flavors below along with some classic ads of kids twisting those delicious cookies.