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
Concert: Friday the 13th – Cook County Jail Concert: Friday the 13th – Cook County Jail Concert: Friday the 13th – Cook County Jail is a live split album recorded at Cook County Jail in October 1972 featuring performances by jazz organist Jimmy McGriff's Quintet with guitarists George Freeman and O'Donel Levy, and saxophonist Lucky Thompson's Quartet which was released on the Groove Merchant label. Allmusic's Scott Yanow said: "This album contains two separate sets that were both performed before inmates at the Cook County Jail one day in 1972. Organist Jimmy McGriff and his quintet performs his lengthy two-part "Freedom Suite," generating a great deal of heat.