If you would like to view the historic performance of a KPI you can easily see each reporting in the KPI History. To get the History, open the KPI and click on the KPI History button.
At the end of each reporting period the KPI performance will be recorded along with a status of Above Target or Below target. The target is defined according to the configuration of the KPI and your KPI settings.
NOTE: The results of each KPI period is locked after completion and are not updated even if the data source has changed. For most data sources this should not pose any problem, however if you have used Google Sheets as your data source and are aware that the data you have supplied in the Sheet has an error please contact the support team to provide further help.