yet let's take a good look at all the police brutality cases that exist hmm? And we don't even need numbers at this point, even you stated, "information is collecting from so many people through surveys that their is no way to check to see if they are lying or not or if the information is really accurate". So we already know that a ton of these reports are filed. And who's gon go out and register a fake report that their dog was killed by police during a swat raid? I guarantee you no one has the time to file something like that with the police, and if it was truly fake, then the police would put it under a completely different category or even trash the entire report altogether
And 10% a huge number in this subject btw dude, considering we're focused on the ENTIRE population of the US and all of these reports that are filed.
Reports: The officers who responded are the ones who write and file the reports. Some officers will blatantly lie on their reports, others will see a lot of stuff in a short period of time that they forget details or they become blurry. However witnesses aren't without faults either since they will undergoe something called the Rashomon effect, I also recommend reading up on the Rashomon effect. The Rashomon effect is where you can have multiple witness see the same event and when you ask them to retell what happened, every witness is going have a different version of the story they are retelling.
Another problem is that information collected from people is collected from telephone surveys and from news crews. There's nothing from stopping me saying "Yeah, my friend of a friend's cousin got his dog shot by cops" or "Yeah I heard from some guy that pigs kicked the door in and blasted his 3 puppies". Basically pepple who want to feel important in front of camera by saying something. The stats can be attributed to the rashomon effect. If there were a quote it would be Remember "there are lies, damned lies, and statistics".
also here is an article can chose to take or not to take with a grain of salt
http://www.washingtonpost.com/news/post-nation/wp/2014/09/08/how-many-police-shootings-a-year-no-one-knows/