The drop, which left the index just short of a 20% slide into so-called bear-market territory, dragged all sectors lower. Even those considered safe, such as healthcare and utilities, have tanked. According to SentimenTrader's Jason Goepfert, this rout has been one of the steepest in percentage terms among the 10 most highly correlated market declines: the drops where stocks have fallen all at once, by similar amounts.