  We study the statistics of citations made to the top ranked indexed journals
for Science and Social Science databases in the Journal Citation Reports using
different measures. Total annual citation and impact factor, as well as a third
measure called the annual citation rate are used to make the detailed analysis.
We observe that the distribution of the annual citation rate has an universal
feature - it shows a maximum at the rate scaled by half the average,
irrespective of how the journals are ranked, and even across Science and Social
Science journals, and fits well to log-Gumbel distribution. Correlations
between different quantities are studied and a comparative analysis of the
three measures is presented. The newly introduced annual citation rate factor
helps in understanding the effect of scaling the number of citation by the
total number of publications. The effect of the impact factor on authors
contributing to the journals as well as on editorial policies is also
discussed.
