That's the statistic for federal grand juries.[1] And it has mostly to do with the fact that federal prosecutors only bring slam dunk cases. At the federal level, there is often a lot of consternation about whether what is being prosecuted should be a crime, but it's very rare that a prosecution is brought on shaky evidence.
At the state level it's much higher 3-4%. You can say it's a rubber stamp, but in practice the average is raised by the fact that most criminal cases are slam dunk (that kilo of cocaine found in the accused's car is almost certainly his). And the bar for an indictment is relatively low, just probable cause. It'd be pretty uncomfortable if prosecuto so we're bringing lots of cases where they don't even have enough evidence to convince 3/4 of a grand jury there is probable cause.
[1] The distinction is relevant because federal and state prosecutors handle totally different sorts of crimes.
At the state level it's much higher 3-4%. You can say it's a rubber stamp, but in practice the average is raised by the fact that most criminal cases are slam dunk (that kilo of cocaine found in the accused's car is almost certainly his). And the bar for an indictment is relatively low, just probable cause. It'd be pretty uncomfortable if prosecuto so we're bringing lots of cases where they don't even have enough evidence to convince 3/4 of a grand jury there is probable cause.
[1] The distinction is relevant because federal and state prosecutors handle totally different sorts of crimes.