Common year starting on Friday has only one Friday the 13th; The only Friday the 13th in this common year occurs in August. Leap years starting on Thursday share this characteristic, but also have another one in February. This is the only year type where the "n"th "Doomsday" (this year Sunday) is not in ISO week "n"; it is in ISO week "n"-1. In the (currently used) Gregorian calendar, the fourteen types of year (seven common, seven leap) repeat in a 400-year cycle (20871 weeks). Forty-three common years per cycle or exactly 10.75% start on a Friday. The 28-year sub-cycle does only span across century
Friday the 13th (1980 film) Left", Cunningham wanted "Friday the 13th" to be more of a "roller-coaster ride." The original screenplay was tentatively titled "A Long Night at Camp Blood". While working on a redraft of the screenplay, Cunningham proposed the title "Friday the 13th", after which Miller began redeveloping. Cunningham rushed out to place an advertisement in "Variety" using the "Friday the 13th" title. Worried that someone else owned the rights to the title and wanting to avoid potential lawsuits, Cunningham thought it would be best to find out immediately. He commissioned a New York advertising agency to develop his concept of the "Friday