The collector of revenue shall collect, deduct and retain for collecting all revenues, taxes, licenses and other dues which he is or may be authorized to collect for the state, city and school the following fees, viz: On current tax revenues, on all sums collected one and one-half percent; on licenses and all other dues, except delinquent and back taxes collected in any one year, as follows: When the amount collected for the city aggregates eight hundred thousand dollars or less, two and one-half percent; on all licenses and other dues collected for the city in excess of eight hundred thousand dollars, four percent; on all such licenses collected for the state, three percent. All such fees herein enumerated shall be deducted and retained by such collector out of the amount collected for state, city and school, respectively, and upon settlement with such collector shall be credited to his account and charged against the respective revenue accounts. On all back taxes, and on all other delinquent taxes, the collector shall charge a fee of two percent which shall be added to the face of the tax bill and collected from the party paying such tax as a penalty in the same manner as other penalties are collected and enforced. The collector of revenue shall pay his salary, and all salaries, clerical hire and other expenses of his office, out of the fees so collected, deducted and retained by him as aforesaid.