Data source is Quinnipiac University Polls (https://poll.qu.edu/new-york-city/?ReleaseID=1832) and the question asked was "Do you approve or disapprove of the way the New York City police are doing their job?".
Original data points are not conistent, with multiple samples in some years and none in others. For years with multiple samples the average was taken, for years with no data (1998 and 2004) the midpoint of the two surrounding years was used and the year flagged with an asterisk.
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