How to measure phone number views without annoying the user?

I'm working on a website where we have customer pages on which we measure user interactions such as opening a booking form or posting a review.

One of the interactions we want to measure is when the users view phone numbers. Currently we do it like this:

Phone 123 - XXX XXX
show number

Show number is a button-link which shows the full number on click and allows us to track the user interaction.

We've recently had some feedback regarding the Xs in the phone number. Our users and customers find it confusing.

The customer information is displayed on one single page and tabs are not an option.

One alternative would be to only have the "show phone number button" without displaying the XXX-version of it.

Any other suggestions?

I'm also looking for good arguments to show the number directly (since, of course, that's best for the user).