  We analyse the monthly sunspot group (SG) data for Solar Cycles C8-C23 and
calculate the average latitude of the drift path for the northern and southern
hemisphere of the Sun. We find that exponential function fits slightly better
than the second-order polynomial to the average drift of the SGs. The drift
velocities are are 0.30 and 0.27 degrees/month (meridional speed about 1.41 and
1.27 m/s) in the beginning and 0.071 and 0.069 degrees/month (about 0.33 and
0.32 m/s) at the end of the average cycle for northern and southern hemisphere,
respectively. We do also bi-linear fits (first-order polynomial fits in two
fractions) because they tell us the crossing point were the drift velocity
changes the most. This crossing point for the Cycles C8-C23 is at 50 months and
15.4 degrees of latitude in the northern hemisphere and 54 months and -14.4
degrees for the southern hemisphere. The drift velocities calculated from the
slopes of the bi-linear fits are 0.233 and 0.216 degrees/month (about 1.10 and
1.02 m/s) before the crossing point and 0.118 and 0.101 degrees/month (about
0.55 and 0.47 m/s) after the crossing point. We find a slight dependence of the
migration on the strength of the cycle such that the drift path of the stronger
cycles follow slightly higher latitudes than those of the weaker cycles. The
areas of the sunspot groups affect also slightly to the drift path such that
large area SGs have path at somewhat lower latitudes in the ascending phase and
higher latitudes in the descending phase of the cycle than the smaller area
SGs.
