Whats up with nicotine statistics on cigarettes within EU vs US? (1mg vs 10mg etc?)

So, I'm a bit confused, in EU theres is a flat 1mg limit on cigarettes, say Marlboro reds are 1mg in EU, I've always thought they're something like 1.1 or 1.2mg in US, now some google results are giving me answers like 10.9mg etc - is this a different way of measuring or what's going on here? From what I thought is that the strongest cigarettes in the US are natural american spirits at like 3mg or so, with the strongest cigarettes around anywhere being the cardboard belomorkanals at like 4mg.