  Using observations of sunspot magnetic field strengths (H) from the Crimean
Astrophysical Observatory (CrAO) and area (S) of sunspots from the Kislovodsk
Mountain Astronomical Station of Pulkovo Observatory, we investigate the
changes in the relation between H and S over the period of about two solar
cycles (1994-2013). The data were fitted by H = A + B log S, where A =
(778+/-46) and B = (778+/-25). We show that the correlation between H and S
varies with the phase of solar cycle, and $A$ coefficient decreases
significantly after year 2001, while B coefficient does not change
significantly. Furthermore, our data confirm the presence of two distinct
populations in distribution of sunspots (small sunspots with weaker field
strength and large sunspots with stronger field). We show that relative
contribution of each component to the distribution of sunspots by their area
changes with the phase of solar cycle and on longer-then-cycle periods. We
interpret these changes as a signature of a long-term (centennial) variations
in properties of sunspots.
