Search-and-Replace with a found number

Hi,
I tried to replace a situation in my text which need to get converted to MOBI:
(any number at the end of the line following a <br>) need to get replaced with (the found number WITHOUT the <br> at the end of the line).

I used the following search term:
((?P<zahl>[0-9])+ <br>)
and the following replacement text:
\g<zahl>

Unfortunately it doesn't work as expected. As a result, always the last number of the whole string of numberstring (ie 1995 only the 5) will be found in the converted text at the end.

I´m unsure where I made the mistake. Are somebody able to enlighten me here?

Thanks a lot!