SIEV X happened in 2001.
let event is X so P(X)=75%=0.75 probabilty that event will not happen P(X')=1-P(X) P(X')=1-0.75 P(X')=0.25 so probabilty that event will not happen is 0.25
Project-X happened in 1992.
X-Perts happened in 1996.
X-Multiply happened in 1998.
Maken X happened in 1999.
X-Scape happened in 2010.
X-Squad happened in 2000.
X-Blades happened in 360.
Insector X happened in 1989.
X-Note happened in 2011.
X-Moto happened in 2005.
X-Wars happened in 2002.