How to align text in SVG horizontally?

Question

SVG

There is a code https://jsfiddle.net/5tnrbr7u/
In it, the text is anchored to the left edge from the beginning of the line above or below which it is located.
The amount of text will change. How can I align the text in the middle relative to the line, so that when the number of characters changes, it will always be centered?