When I compare my tax burden in one country vs. what I would be paying had I been living in another country, I would not use the measure of "Tax revenue as shar

When I compare my tax burden in one country vs. what I would be paying had I been living in another country, I would not use the measure of "Tax revenue as share of GDP". This is the first time I came across such a way of defining the total tax percentage. Is this include corporate income tax, capital gains tax, personal income tax, social-security payments rolled into one? If so, then it makes sense, as the US has low corporate and cap gains taxes.