The darker of the colour, the more common that birthday is.

• Most people are born in August & September (and therefore were conceived around November & December, think winter nights in?)
• However, very few people are actually born during holidays – New year, Independence day, Halloween, Thanksgiving and Christmas. (People don’t like to spoil their holidays?)
• Few people are born on the 1st of April. (You don’t want your kid born on Fool’s Day)
• Few people are born on the 13th of any month. (Unlucky?)
• Plenty are born on Valentine’s Day and St Patrick’s day