Measures can be copied. There are two different ways of copying a measure:

Option 1

To build a similar measure with small changes, click on the three dots and  'Make a copy.'

Option 2

To add a measure to a previous reporting year to enable historical data, enter the measure builder view. Click on the 'Export' button and 'Copy to clipboard.' Enter the measure builder view for the new measure. Update the reporting year to the year required. Click the 'Import' button and paste the code into the editor. Import and save the measure. 

If you are making changes to a measure from one year, you will need to update the measure in the other years.