@firefly,
I have yet to find the figure for New York State but the true bill rate in the US seem to run to 99 percents or so.
http://en.wikipedia.org/wiki/Grand_jury
In Kentucky, grand jurors are empaneled in each county, at the Circuit level (felonies only) for a four-month term (three panels per year). During the trial jury orientation for the given four-month term, the grand jurors are selected from the trial jury pool, although the method of selection is not necessarily random. The meetings are twice a month (however, grand juries in more populous counties generally meet more often), with each meeting usually going through 20-30 cases in a four to five hour period. The indictment rate is about 98-99%; the grand jury can broaden (about 1% of the time) or narrow (about 3% of the time) the counts in the indictment as well. Usually, fifteen or so[clarification needed] grand jurors are required to report to meetings; the hope is that twelve will show to each meeting, which is the number of jurors required to hear cases (extra jurors can leave). It takes nine yes votes to the question of probable cause to sign a true bill of indictment. Fewer than nine yes votes either causes a no true bill or a narrowing of the indictment (depending on the votes per count).
CriticismThe most persistent criticism of grand juries is that jurors are not a representative sampling of the community, and are not qualified for jury service, in that they do not possess a satisfactory ability to ask pertinent questions, or sufficient understanding of local government and the concept of due process.[21] Unlike potential jurors in regular trials, grand jurors are not screened for bias or other improper factors. They are rarely read any instruction on the law, as this is not a requirement; their job is only to judge on what the prosecutor produced. The prosecutor drafts the charges and decides which witnesses to call.[9] The prosecutor is not obliged to present evidence in favor of those being investigated. Grand jury witnesses have no right to have a lawyer or family in the room, and can be charged with holding the court in contempt (punishable with incarceration for the remaining term of the grand jury) if they refuse to appear before the jury[22] and all evidence is presented by a prosecutor in a cloak of secrecy, as the prosecutor, grand jurors, and the grand jury stenographer are prohibited from disclosing what happened before the grand jury, unless ordered to do so in a judicial proceeding.[9]
After a grand jury was commissioned to investigate whistleblowers organization WikiLeaks, grand juries have been accused of being used as an intimidation and persecution mechanism against whistleblowers and anti-war activists.[23]