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Fig. 22

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The redshift distribution of quasars from this catalog is displayed in black. The same distribution is shown for newly discovered quasars only (dashed blue histogram). Most of the SDSS-DR9 quasars have a redshift greater than 2. The redshift distribution of quasars from the SDSS-DR7 catalog (Schneider et al. 2010) is shown for comparison in red. The latter is dominated by quasars at low redshift. The present catalog contains 2.6 times more quasars at z > 2.15 than the DR7 catalog.

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