Hmm.
I manage do do it in October.
But when when i try to it for example for June it does not work.
What do I do wrong?

=SUMPRODUCT((SUBSTITUTE(LEFT(A1:A19,6),".","-")+0>=B1)*(SUBSTITUTE(LEFT(A1:A19,6),".","-")+0<=B2))

B1 = 1-June
B2 = 31 June