"are all of your opinions based on guesses?"

Prove me wrong. It's what is NOT accounted for in the polls yet a huge problem for law enforcement having people come forward.

"The largest number of gangs are said to be in Hackney, east London (22 gangs); Enfield in north London (13); Lambeth and Merton in south London (12 gangs each); Waltham Forest in north east London (11) and Brent in north west London (11).

Gangs were found to have around 20 to 30 members, and to commit crimes in smaller groups of three to six. "

Whereas direct from the FBI:

"About 20,000 violent street gangs, motorcycle gangs, and prison gangs with approximately 1 million members are criminally active in the U.S. today. Many are sophisticated and well organized; all use violence to control neighborhoods and boost their illegal money-making activities, which include drug trafficking, robbery, theft, fraud, extortion, prostitution rings, and gun trafficking. Here, you'll find more on the threats posed by gangs, on how you can help spot and prevent gang activity, and on how we're redoubling our efforts to disrupt and dismantle them through intelligence-driven investigations and new initiatives and partnerships."