  We identified three samples of ROSAT sources with Sloan Digital Sky Survey
spectra, one at redshift z = 0.1, a second one at z = 0.2 and a third one at z
= 0.3. 812 sources in total were examined. We determined the nature and
spectral sub-types of the sources by visual inspection. The fraction of each
sub-type at each of the three redshifts are then calculated. We consider
selection biases caused by the luminosity cut-off threshold to determine
whether any systematic trends in AGN type are evident with increasing redshift.
We hence probe if an evolution effect is detected in our sample.

Astrophysics of Galaxies