Over 78 000 RR Lyrae Stars in the Galactic Bulge and Disk from the OGLE
  Survey
  We present an upgrade of the OGLE Collection of RR Lyrae stars in the
Galactic bulge and disk. The size of our sample has been doubled and reached 78
350 RR Lyr variables, of which 56 508 are fundamental-mode pulsators (RRab
stars), 21 321 pulsate solely in the first-overtone (RRc stars), 458 are
classical double-mode pulsators (RRd stars), and 63 are anomalous RRd variables
(including five triple-mode pulsators). For all the newly identified RR Lyr
stars, we publish time-series photometry obtained during the OGLE Galaxy
Variability Survey.
  We present the spatial distribution of RR Lyr stars on the sky, provide a
list of globular clusters hosting RR Lyr variables, and discuss the Petersen
diagram for multimode pulsators. We find new RRd stars belonging to a compact
group in the Petersen diagram (with period ratios P_1O/P_F = 0.74 and
fundamental-mode periods P_F = 0.44 d) and we show that their spatial
distribution is roughly spherically symmetrical around the Milky Way center.
