I chuckled, so up arrow for you.
For data, looking at the COPA website, I see 37 Firearm Discharge logs created for 2020 and another 19 through the end of May 2021.
It's been a while, but I'm pretty sure that COPA (and their predecessor) investigate _all_ firearm discharges.
However, each "log" may contain multiple TRR (Tactical Response Report, which is where firearm discharges are documented), one for each officer involved in a single case. So, for a large response, there could be five or more officers who discharged their service weapon attached to a single log.
I am really curious how large of an increase in ShotSpotter reports around 4JUL due to actual fireworks. Of course, shootings also rise considerably during the 4th in Chicago as well -
2021 - 23 killed, 90 wounded 
2020 - 21 killed, 71 wounded 
Also, I wonder what ShotSpotter considers a report? Is there one generated for every single sound that it registers as a "probable gun" or does it group multiple noises in close proximity (both time and location) as a single report?
Of course, being statistics, some phrase about lies and damn lies come to mind.
 Stats provided by HeyJackass! :)