If you want to create a user attribute for something like a salary range, use a "Numeric Range" instead. Note that numeric ranges have to be whole numbers and define a field as ranges.
Setting Up a Numeric Range
Step 1: Navigate to your "Admin" panel
Step 2: Under "People" click on "User attributes"
Step 3: In the top right corner, click on "Create custom attribute"
Step 6: Choose the "Number" attribute type
Step 7: Give your attribute a name, visibility, and add your ranges
The ranges work in a way where the low range is included but the higher range is excluded. For example, if you have a numerical range from "0 to 5", the first range will include numbers "0, 1, 2, 3, and 4", but will exclude the number 5. The next range will include the number 5.