What values do we get on the y axis when we use xcorr function between 2 different signals?

Hii!

I am writing a matlab Code to check the similarity between 2 ECG signals. I have filtered the ECG signals by removing the high frequency noise and removing the baseline wandering.

I have used Xcorr to check the similarity between the two ECG signals. In the y axis I am getting some values greater than 1.

Can someone please let me know what the values on y axis are?

I have attached my correlated output signal.