From the 2003 Jewish Federation Survey:
Neighborhood # Jews % O # O
Williamsburg 52,700 94% 49,538
Flatbush/Midwood/Kensington 101,100 54% 54,594
Borough Park 76,600 74% 56,684
Fresh Meadows/KewGardens Hills/Hillside 28,200 51% 14,382
http://www.jewishdatabank.org/Archive/C-NY-New_York-2002-Geographic_Profile_Report.pdf