In my post on EU-US convergence, I found that the US was similar to the leading eurozone countries in both productivity (output per hour worked) and employment-population ratio, so that the difference in income per person is mostly explained (in some cases more than explained) by differences in hours worked per employment person. I didn’t take the distribution of income into account, since the data sources I was using there did not provide anything useful. But commenter Detlef found a blog post by Maximilian Hagemes at the World Bank site which links to a useful paper by Piketty and Alvaredo on cross-country comparisons of income concentration. For most eurozone countries, they show that the top 1 per cent of households gets about 8 per cent of total income (the presentation is graphical, but in any case, there is no point in going for spurious precision with numbers like this). For the US, the most recent data gives an 18 per cent share. So, the share of national income going to the remaining 99 per cent is about 10 per cent smaller in the US than in the eurozone.
There are a couple of ways of looking at this.