Since it is not comparing apples to apples and, as you said, is very raw data, I think the per capita comparison has very little substance to it and is an easy way to skew the data to fit one side of an argument. You know, the media's SOP. It is a gross number that has to be used in comparison but is very misleading if it is the only data used.
The raw data and the per 'x' number are two different things really.
Comparing the raw numbers is like comparing apples to elephants - entirely useless.
Comparing with per capita is the closest we can get to apples Vs apples - it's like braeburn Vs granny smith - still not ideal but the best we have.
I tried to support the immigrant numbers you listed and while I found the same numbers I also found much wider numbers so I do not know what is accurate. I know nothing about immigration in your neck of the woods so I do not know if it is a problem for you society/cultural wise or
The numbers for immigration are always wildly disparate...
It's very rarely published as to what basis is used - is it immigrants this year, does it include illegal traffic, does it include those with a visa (valid, misused or expired), does it include those that have been nationalised, first generation, second/third, those that arrive as infants?
Due to the fact that every single 'study' provides a different figure the only real (fairly quick) way to drag out a comparison is to Google "US population immigrant percentage" and the same for UK - and take the first result.
With some digging I could very likely find data to support any number between 0.00001% and 99.9999% for either location.
Some sources say it's a massive problem here, some say it's not an issue worth worrying over - and all sides have a political agenda behind them so I literally cannot draw any definite conclusion I trust myself, let alone expect others to trust.
Illegal aliens are a big problem here and contribute heavily in regards to major crimes.
I obviously can't speak to your location but here (bearing in mind my above comment) I can't say that's really the case.
Illegals are instrumental (by coercion or choice) in major crimes like drug trafficking and human trafficking, prostitution, etc. and all manor of less major crimes - but it's a small percentage of the total illegals involved (most are simply trying to get by and hide) and very rarely in charge.
We have far larger problems with people who are here perfectly legally to be honest (and that's a comparative larger, not a countrywide issue affecting everyone directly).