Depends greatly by country. In the US, the total tax wedge (which includes
employer tax contributions, such as payroll taxes) is 31.7% of total labour costs[1]. In the UK it is 30.8%, while e.g. in Denmark it is 36.4%. The OECD average is 35.9%
Belgium is the extreme - at 55.3% it's the highest in the OECD. Three European countries (UK, Ireland, Switzerland) come in below the US on this metric.
The numbers are basically all over the place, and depends more on overall culture and priorities than things like healthcare etc. by themselves.
In terms of what is directly visible to the employee, US is at 25.6% of gross wages (note the difference - these numbers can not be directly compared to the ones above, as the ones above are percentages of total labour cost including the employer contributions) compared to 23.4% for the UK, 36.1% for Denmark (Denmark is one of very few countries that don't "hide" hardly any of labour costs as part of employer social security contributions), or 28.4% for Norway, 24.7% for Sweden or 42% for Belgium. So still all over the place.
It also depends greatly on how much you earn, and how progressive your specific country's tax system is.
The only thing that's clear is that the US does not stand out as being nearly as much of a low tax country as people sometimes like to think. E.g. the OECD average (which to be fair is pulled down by several non-European countries) of employee contributions is 25.5%, so slightly below the US.
[1] http://www.keepeek.com/Digital-Asset-Management/oecd/taxatio...
[2] http://www.keepeek.com/Digital-Asset-Management/oecd/taxatio...