"Fewer than 10 percent of the criminal cases brought by the
federal government each year are actually tried before
juries with all of the accompanying procedural safeguards
noted above. More than 90% of the criminal cases in America
are never tried, much less proven, to juries. The
overwhelming majority of individuals who are accused of
crime forgo their constitutional rights and plead guilty."[1]
From what I've read elsewhere, of the 10% or so that do go to trial, something like 9 times out of 10 the verdict is guilty. Given that a federal criminal trial takes $1.5 million to defend and that the prosecutor has all the weight and resources of the federal government behind then and the citizen has to rely on his own financial resources (which are likely to be frozen if they are well-heeled defendants), then that rate of conviction isn't surprising in the least. Federal criminal cases are totally asymmetric in favor of the federal government. As citizens, we always complain of well funded people prevailing in civil and criminal cases because of the money they have to defend themselves, but we ignore the well funded prosecution that US district attorneys have that allow them to consistently find people guilty who may not be.
[1] http://www.cato.org/sites/cato.org/files/serials/files/regul...