The current best estimate of the Galactocentric distance of the Sun
  based on comparison of different statistical techniques
  In this paper, the current best estimate of a fundamental Galactic parameter
Galactocentric distance of the Sun $R_0$ has been evaluated using all the
available estimates published during the last 20 years. Unlike some other
studies, our analysis of these results showed no statistically significant
trend in $R_0$ during this period. However we revealed a statistically valuable
improvement in the $R_0$ uncertainties with time of about 0.2 kpc for 20 years.
Several statistical techniques have been used and compared to obtain the most
reliable common mean of 52 determinations made in 1992--2011 and its realistic
uncertainty. The statistical methods used include unweighted mean, seven
variants of the weighted mean, and two variants of median technique. The $R_0$
estimates obtained with these methods range from 7.91 to 8.06 kpc with
uncertainties varying from 0.05 to 0.08 kpc. The final value derived in this
analysis is $R_0 = 7.98 \pm 0.15\,|_{stat} \pm 0.20\,|_{syst}$ kpc, which can
be recommended as the current best estimate of the Galactocentric distance of
the Sun. For most of the practical applications the value of $R_0 = 8.0 \pm
0.25$ kpc can be used.
