If Statements not generating number values for later formulas?

Hi all! I just started doing taxes as a small business and I figured I’d make an airtable chart to keep track of all the different tax rates in different counties. However, what I’m running into is this:

When I go to formatting I get the response: Your result type is not a number or a date. Formatting options are currently only available if your result type is a number or a date.

Here is my formula:

IF(
    SEARCH("Online", {Location}),
    "0%",
    IF(
        SEARCH("Wake", {Location}),
        "2%",
        IF(
            SEARCH("Durham", {Location}),
            "2.25%"
        )
    )
)

I’ve tried both with and without the % symbol.

To be fair, the return in that column works fine but I can’t then make a later formula using those values because it doesn’t recognize them as numbers. Here’s a screenshot of the table

I saw in another thread that maybe doing a separate tax rates table would help, but I am unsure how to set it so that if I click “Durham” on my Location it would apply the Durham Tax Rates to the rest of the line. However, that method might be more useful in the long run since I could easily change one number on one spreadsheet rather than updating each individual column’s IF statement.

Any assistance is appreciated! I haven’t done a ton of formula building with airtable and find it a bit more difficult than sheets/excel.