Topple rate (Decrepitude rate)

Global phenomenon that is being attributed mainly to technology developments and fast paced business competition. It is the rate at which industries loose their leading positions over certain periods of years. For example, “midrange” computer industry that became extinct gradually within 20 years between 1970s and 1990s, i.e. Topple rate at this case is about 20 years. It is said that the occurrence of such effect is healthy within advancing economies.