120,000 quasars, only four of them seemed to act as a gravitational lens.

quasar SDSS J0013+1523
Astrophysicists discover a quasar that acts as a cosmic lens (w/ Video)
contains nearly a million galaxies and over 120,000 quasars.
A sample of some 23,000 of these quasars in the northern hemisphere was selected by the Laboratory of Astrophysics team.
In the end, only four of them seemed to act as a gravitational lens.
http://www.physorg.com/news198859065.html
Reverse cosmic lens advances quasar studies | W. M. Keck Observatory
the quasar is 1.6 billion light years from Earth and lenses a galaxy roughly 7.5 billion light years away.
http://keckobservatory.org/index.php/news/reverse_cosmic_lens_advances_quasar_studies/
Discovery of a Triple Quasar
http://www.astro.caltech.edu/~george/qsolens/