  We present high-accuracy rotation curves, which show a steep nuclear rise and
high-velocity central rotation, followed by a broad maximum in the disk and
flat part. We use the rotation curves to directly calculate the radial
distribution of surface mass density, and obtain radial variations of the
mass-to-luminosity ratio (M/L). The M/L ratio and, therefore, the dark mass
fraction (DMF) is not constant at all, but varies within the bulge, increases
already within the disk, and rapidly from the disk toward halo. In some
galaxies, the DMF within the bulge increases inward toward the center,
indicating a massive dark core.
