This file is from Wikimedia Commons and may be used by other projects.
The description on its file description page there is shown below.
Summary
DescriptionPublic Approval of NYPD since 1997.png
English: Time series of public approval of NYPD.
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.
to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.