Without further ado

1. Although you might celebrate your birthday every year, your actual birth day only occurs once every 7 years! Not counting leaping years, the date you were born on moves each year to the following day of the week. For example, if you were born on Saturday March 15th, the following year, March 15th will fall on a Sunday, the year after on a Monday, and so on. This means your annual celebration is actually for your birth date - not your birthday - and in truth your birth day (the actual day you were born on) occurs only every 7 years!
2. Until quite recently, most Japanese children used to celebrate their birthdays on January 1st, regardless of which day of the year they were actually born on. Today however, most Japanese children celebrate on their actual birthdays
3. Hallmark alone makes more than a half a billion birthday cards each year.
4. The average American receives eight birthday cards and four gifts a year
5. Consumers write additional messages inside a birthday card 70 percent of the time.
6. 50 percent of all partyware is for birthdays, and 65 of that 50 percent is kids partyware
7. About 5 million people celebrate birthdays in the U.S. each week; an average of 700,000 birthdays occur each day.
8. Birthday cards are 62 percent of the everyday occasion card industry
9. Middle age changes according to life expectancy: As life expectancy and longevity increase, middle age tends to be older. With more people living beyond 100 (108,000 and that number is projected to double by 2010), 50 seems "young." (Only about 10,400 people were 100 years old in 1960.)
10. For Americans, birthdays are the #1 reason to party.