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 motorcycle rally 90,000 to more than 170,000. An attempt in 2008 to surpass the previous Guinness world record for the largest motorcycle parade failed due to a technicality. More than 10,000 motorcycles would have exceeded the record set in 2006 by the Republic of Texas Biker Rally. Although the organizers were able to document participation by more than 12,000 motorcycles at Port Dover, they entered through multiple portals to the city and were disqualified by Guinness as a single parade. Friday the 13th motorcycle rally The Friday the 13th Motorcycle Rally is a motorcycle rally held every Friday the 13th in Port