Almost everyone loves chocolate chip cookies. May 15 is National Chocolate Chip Day.

That's a good reason for people to eat more of the chewy treat than usual.

Even though people love the cookie, there are some interesting things they might not know about the sweet treat.

1. An accident

In 1937, Ruth Graves Wakefield, owner of the Toll House Inn in Whitman, Massachusetts, ran out of baker's chocolate.

As a substitute, she put broken pieces of a chocolate bar into her cookie dough. She thought the pieces would melt, but they didn't.

2. Size of a quarter

The original cookie was extremely crispy and was the size of a quarter. Because it was so small, it could be consumed in only one bite. Today, the cookie comes in various shapes and sizes. Many people are glad the size is much larger than a quarter. One medium cookie that is three inches in diameter contains 78 calories. Of course, larger ones will have more calories.

3. A lifetime supply of chocolate

Nestlé bought Wakefield's recipe in 1939. The company did not give her money.

Instead, she was paid with a lifetime supply of chocolate. Her recipe is found on every bag of Nestlé Chocolate Chips. Check this out the next time you purchase a bag.

4. America's favorite

Of all the cookies available, it's America's favorite. Polls indicate that 53 percent of American adults prefer chocolate chips over other kinds, according to American Profile. The next favorite is peanut butter with 16 percent followed by oatmeal with 15 percent. Today, 25 percent of all cookies baked and sold in the United States are chocolate chips.

5. Two national days

There are two days a year that celebrate the delicious treat. May 15th and August 4th are National Chocolate Chip Days. Because of its popularity, it became the official cookie of Massachusetts on July 9, 1997.

The suggestion came from a third grade class in Somerset, Massachusetts.

6. A drop cookie

The chocolate chip is a drop cookie. That's because small portions of the dough are dropped from a spoon onto a baking sheet. They are baked for about 15 minutes in the oven until they are done. The dessert or snack can be eaten hot or cold.

7. Ingredients

The cookies are easy to make with a few ingredients that include flour, eggs, butter, sugar, salt, and vanilla extract. Semi-sweet was the original flavor of chocolate chips. Today, bakers have choices of including bittersweet, semi-sweet, dark chocolate, white chocolate, mint, milk chocolate, or white and dark swirled.