Americans love hot dogs so much that the month of July is all about celebrating this fast food treat, culminating in Hot Dog Day on July 23.

The humble hot dog is an integral part of US culture, and it’s hugely popular, with hot dog carts on street corners, people chowing down at sporting events, and making their own at backyard barbecues.

In fact, the National Hot Dog and Sausage Council (NHDSC) estimates Americans eat 20 million hot dogs every year, which equates to around 70 per person!

The fun facts don’t stop there either – here are 10 things you might not know about hot dogs in America.

 1. It's all about the mustard

What's your favourite hot dog topping? According to data released by the NHDSC, nearly 71% of Americans surveyed nominated mustard as their first choice of topping.

2. Ketchup is frowned upon – mostly!

The NHDSC’s rules of etiquette say you can't have ketchup on a hot dog after the age of 18. Many clearly flaunt this rule, however, as ketchup is the second most popular topping choice across America.

3. Baseball fans are among the biggest consumers

Americans just love digging into a dog at sporting events, especially baseball games. It's estimated that baseball fans ate 18.5 million hot dogs during the Major League Baseball season in 2015.

4. Hot dogs to honour the Olympics

American company Sara Lee created a massive hot dog in honour of the 1996 Olympics in Atlanta. If you can believe it, the dog was just over 600 metres long!

5. You shouldn't use a fork to cook a hot dog

You should only use a spatula or tongs to cook a hot dog. This is because they may lose moisture when they're pierced by a fork, as the juices run out.

6. Hot dogs are fit for visiting royalty

Americans have never been shy when it comes to sharing their love of hot dogs. In 1939, President Franklin D. Roosevelt served frankfurters to King George VI, which resulted in the term 'hot dog summit'.

7. The term 'hot dog' has mysterious origins

Hot dog historians are still unsure about who coined the term 'hot dog'. One story is that vendors in 1901 started shouting, "Get your dachshund sausages while they're red hot!". Another states that New York Journal sports cartoonist, Tad Dorgan, drew a cartoon of barking dachshund sausages in rolls, writing 'hot dog' as the title. However, the cartoons have never been found.

8. Hot dog eating contests are still famous

Coney Island in Brooklyn New York and hot dogs go hand in hand, thanks to Nathan's Famous flagship restaurant. This year on the 4th of July, the restaurant's 100th anniversary will be celebrated with The Nathan's Famous Hot Dog Eating Contest.

9. American hot dogs can be pricey

According to the Guinness Book of Records, the world's most expensive hot dog was sold by Tokyo Dog in Seattle for a whopping $169!

10. No one really knows who invented hot dogs

A hotly contested subject, the exact origin of the hot dog is not proven. The most logical story is that they began in Frankfurt, Germany, hence the term 'frankfurter'. As to who decided to put the sausage in the bun…the jury's still out.

Now that you're full of fun hot dog facts, you can hold your own trivia game during July to celebrate!