You can read more information about reporting here:
[Guide] Reporting effectively.
There is no limit to how many posts you can report. Once you have 300 good reports, you will see additional information regarding your reports on the
"Your reports" page. I have never heard of someone being banned from reporting too much, but I suppose it is possible if you absolutely flood the moderators with fake reports. All that usually happens if your reports are incorrect is that they are marked bad (and your accuracy will drop).
From your picture, you have 9 reports - 1 of these was bad (and a couple are still to be handled), hence the 86%. As it says, don't worry too much about your accuracy.
