Friday the 13th etc.) of the year. Any month that starts on a Sunday contains a Friday the 13th, and there is at least one Friday the 13th in every calendar year. There can be as many as three Friday the 13ths in a single calendar year; either in February, March and November in a common year starting on Thursday (such as 2009, 2015 or 2026) (D), or January, April and July in a leap year starting on Sunday (such as 2012) (AG). The longest period that occurs without a Friday the 13th is 14 months, either from July to September the following
Black Friday (shopping) was the first to launch a special Black Friday promotion. The year after, most Swiss retailers launched special offers during the Black Friday Week. It is estimated that customers spend around 80 million Swiss Francs in onlineshops alone on Black Friday 2017. In recent years, Black Friday has been promoted in Australia by in-store and online retailers. In 2011, Online Shopping USA hosted an event on Twitter. Twitter users had to use the hashtag #osublackfriday and it allowed them to follow along and tweet favourite deals and discounts from stores. In 2013, Apple extended its Black Friday deals to Australia.