Problem with the serial monitor

I made an activity to measure distances by ultrasound, but when I want to see the results on the serial monitor this writes all in the same line.
Like this:
"El nivel de luz es 21%El nivel de luz es 23%..."
I don't know how to solve this because in the rest of the activities it was written well.

Thanks in advance

Read read this before posting a programming question, follow the advice and post your code