They found guns in 1.9% of the stop and frisks. That's the ostensibly reason for stop and frisk.
http://www.nyclu.org/files/publications/NYCLU_2011_Stop-and-Frisk_Report.pdf
DATA HIGHLIGHTS
The 685,724 stops in 2011 (an increase of 14 percent from 2010) were spread unevenly
amongst the citys 76 precincts, with the 75th Precinct (East New York) leading the city
with 31,100 stops. Setting aside the Central Park Precinct (22nd), the 94th Precinct
(Greenpoint) had the fewest stops at 2,023.
In 70 out of 76 precincts, black and Latino New Yorkers accounted for more than 50
percent of stops, and in 33 precincts they accounted for more than 90 percent of stops. In
the 10 precincts with the lowest black and Latino populations (such as the 6th Precinct in
Greenwich Village), blacks and Latinos accounted for more than 70 percent of stops in
six of those precincts.
Young black and Latino men were the targets of a hugely disproportionate number of
stops. Though they account for only 4.7 percent of the citys population, black and Latino
males between the ages of 14 and 24 accounted for 41.6 percent of stops in 2011. The
number of stops of young black men exceeded the entire city population of young black
men (168,126 as compared to 158,406). Ninety percent of young black and Latino men
stopped were innocent.
Though frisks are to be conducted only when an officer reasonably suspects the person
has a weapon that might endanger officer safety, 55.7 percent of those stopped were
frisked. Of those frisked, a weapon was found only 1.9 percent of the time.
Frisks varied enormously by precinct, with officers in the 46th Precinct in the Bronx
frisking people 80.4 percent of the time, as compared to a low of 27.5 percent in the 17th
Precinct on the East Side of Manhattan.
Black and Latino New Yorkers were more likely to be frisked than whites and, among
those frisked, were less likely to be found with a weapon.
In 2011 as compared to 2003 (the earliest year a gun recovery figure is available), the
NYPD conducted 524,873 more stops but recovered only 176 more guns. This amounts
to an additional recovery rate of three one-hundredths of one percent.
Of the 605,328 stops of innocent people in 2011, 53.6 percent were frisked. The 75th
Precinct led the city in stops of innocent people with 27,672 such stops. Excluding the
Central Park Precinct, the 94th Precinct had the fewest with