Overall turnout in Mayoral elections in New Zealand

Residential voters: Are voters living within the electorate
Ratepayer voters: Are voters living outside the electorate but eligible to vote because of property ownership within the electorate. In some cases the number of ratepayer voters exceeds the number of listed ratepayer electors because additional ratepayers registered after the elector list was published.

Blank votes (%) = the number of blank votes cast (including special votes) divided by the total number of voters
Candidates community board members (%) = the number of community board members from previous term who stood for council in current election, divided by the total number of candidates in current election (city and district council elections only)
Candidates sitting members (%) = the number of sitting members in previous term who stood for re-election in current election divided by the total number of candidates in current election
Community board members elected (%) = the number of community board members in previous term who stood for council in current term and were elected, divided by the total number of positions in current term (city and district council elections only)
Elected unopposed = number of elected members, where the number of candidates is equal to, or less than, the number of positions
Electors per position = the number of electors (residential and ratepayer, where applicable) divided by the total number of positions
Resident population = the estimated population usually resident of the area, based on estimated or Census data (provided by Statistics New Zealand)
Informal votes (%) = the number of informal votes cast (including special votes) divided by the total number of voters
Members elected (%) = the number of sitting members in previous term who stood for re-election in current term and were re-elected, divided by the total number of elected members in current term
Ratepayer electors (contested areas only) = the total number of ratepayer electors on the roll in contested areas (used for calculating ratepayer turnout)
Ratepayer electors (%) = the total number of ratepayer electors on the roll, divided by the total number of electors on the roll
Ratepayer turnout = number of ratepayer voters (including those who cast special votes and these were allowed in respect of their ratepayer qualification) divided by the number of ratepayer electors on the roll in contested areas
Residential electors (contested areas only) = the total number of residential electors on the roll in contested areas (used for calculating residential turnout)
Residential turnout = number of residential voters (including those who cast special votes and these were allowed in respect of their residential qualification) divided by the number of residential electors on the roll in contested areas
Sitting mayor (R/S/U/D) = whether the sitting mayor in previous term was: re-elected (R); stood down (S); re-elected unopposed (U); or defeated (D) in the current elections
Sitting members re-elected (%) = the number of sitting members in previous term that were re-elected in current term, divided by the total number of positions in current term
Special votes allowed (%) = the number of allowed special votes (residential and ratepayer) divided by the total number of special votes cast
Special votes cast (%) = the number of voters who cast special votes divided by the total number of voters
Total electors (contested areas only) = the number of residential and ratepayer electors for all contested areas (used for calculating total turnout)
Turnout = number of voters (including those who cast special votes and these were allowed) divided by the number of electors on the roll in contested areas
Women candidates (%) = the number of women candidates divided by the total number of candidates
Women members/councillors (%) = the number of women elected divided by the number of positions
Voters per position = the number of voters (residential and ratepayer) divided by the number of positions
Voting document order (A/R/P) = the order candidates were listed on the voting document: alphabetical order (A); random (R); or pseudo-random (P)

At URL provided, under 'Data', select 'Local Authority Election Statistics 2022 (Excel, 346 kb)'.
Figure.nz edited the file for processing purpose.

The Department of Internal Affairs compiles voting statistics from local authority elections (local elections), which are held every three years. Local authorities include city, district and regional councils, district health boards (DHBs), local and community boards, and trusts (such as licensing trusts).

The Electoral Commission provides information on turnout at General Elections.