The following table gives the literacy rate (in percentage) of 35 cities. Find the mean literacy rate.
Literacy rate (in %)45−5555−6565−7575−8585−95Number of cities310118 \begin{array}{|c|c|c|c|c|c|} \hline \text{Literacy rate (in \%)} & 45 - 55 & 55 - 65 & 65 - 75 & 75 - 85 & 85 - 95 \\ \hline \text{Number of cities} & 3 & 1 & 0 & 1 & 18 \\ \hline \end{array} Literacy rate (in %)Number of cities45−55355−65165−75075−85185−9518