Statistical key figures of different types cannot be added together

What causes this issue?

You have tried to add together statistical key figures of different
types. Fixed value key figures, such as employees, cannot be added
cumulatively over the fiscal year. Other statistical key figures, such
as telephone units, are added to form a total for the year. If only one
of these key figure types exist, you can create a total for the year
provided the units are the same.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Since you cannot create a total in this report, you must suppress
totalsformation for statistical key figures.
There are two ways to do so.
Change the definition of the report. In the "Environment" menu, use the
function "Define reports". Here you must select "Report" and then
"Change". You can now access the the row definition directly. You
suppress totals formation for rows with statistical key figures. To do
so, set the totals level to 1-.
In general set maintenance, you can delimit the row with the
statistical key figure. Instead of the definition "Display all stat.
key figures", you can change the definition to "Display statistical key
figures Employees 1 and Employees 2". Totalling then takes place
through these two key figures only. The definition in general set
maintenance must afterwards be assigned to the report.

Error message extract from SAP system. Copyright SAP SE.