Showing Incorrect Data without Data Interpreter

I have a dashboard that is showing incorrect data in Tableau Desktop version 2020.1.2 unless I turn the Data Interpreter on.

Here's the data from the Excel data source when accessed directly in Excel:

And when accessed via Tableau Desktop (i.e. it's showing the same data):

But Tableau Desktop is changing the 97% and 90% values to 100% and the 2.10% value to 0%:

Unless I turn the Data Interpreter on:

I am attaching the results from the Data Interpreter, but it looks like all it did was ignore the blank data from June through December.

Is there a reason it's changing the data values?

Thanks,

Liz