Histograms of central stars masses. From top to bottom we compare our population synthesis results (see also Fig. 11), the Galactic sample of Gorny et al. (1997; photometric method), the Galactic sample of Rauch et al. (1998, 1999) and Napiwotzki (1999; spectroscopic method), the combined LMC and SMC samples of Villaver et al. (2003, 2004), Jacoby & Kaler (1993), Dopita et al. (1997), and Liu et al. (1995), and, finally, the WD sample of Liebert et al. (2005). The vertical line marks central star mass 0.56 M_⊙.