No email template statistics

No email template statistics

Hi all

After successfully creating a few Lead email templates and using them for a couple of months now, I would like to check the statistics, like opening rate or click rate.
My problem is, there are non! Not even the count is correct. Of maybe 50 emails sent (one by one), the system shows me 2 emails sent and 0 opened. These super low numbers appear in all the different templates.

What did I do wrong?
How come the systems counts only a very few and ignores the rest?
Is there a configuration I missed?

Thank you very much in advance!