netstat -an
will give you active connections, along with EVERYTHING else. This includes things like listening ports etc..
If you are limited to only using netstat, you should be able to count out the number of established connections using something like:
netstat -an | grep -w "<listening ip>:80" | grep ESTABLISHED | wc -l
which is a bit of a hack, but works by just counting the number of established connections coming in to your listening ip, on port 80.
If you can install ss, or have it already installed:
ss -nt dst <ip webserver is listening on>:80 | wc -l
The above should give you a count of all connections with a destination of your listening ip address on port 80.
If you are looking for unique connections you could even narrow it down more by using "sort" and then "uniq -c" (foregoing "wc -l") to get a count to unique connections as well.
ss is super useful: https://linux.die.net/man/8/ss