Brazilian Taxes
(Another way to approach = "Its know" or "its widely known that"... your sentence is not grammaticaly wrong but just a bit awkward, and by using this you would also avoid repeting the word "world " twice =)

)I think most of the people in the world know that Brazil is the country that collects the highest quantity of money in taxes in the world. Everything that we buy and even everything that we sell takes moremoney than. ( More than half of the money we spend is taken by the government)
Employees must pay part of their salaries and employers must pay a tax ( that comes from their employees payment) on the salary they give to their employees and, depending on the amount of money that this salary consists in, the taxes can be really high are very high.
But the real problem is not that. But that's not the real problem
The Constitution of 1988, which is still used until now today, says that the State is obliged (=must) to give provide the population people with the best health care, good health system, good education, residence conditions and a lot of other things and so forth, without those people needing to pay for that ( I don’t know if its right but in these case as the first one at the first top I would say something like = “ without them having to pay even more for it. ). (if im not mistaken=) I'm not sure, but I believe that half of what’s the taxes payed by the Brazilians that Brazilian people pay should be enough to make the Government comply with its obligation.
But, even with all the taxes and all the money that is taken away from people every year, we don't see (= it being applied in anything) anything good. People who have has money can afford paying for good education, good hospitals and safety, while people who don't doesnt, have to accept tough living conditions -the same conditions. Having to deal with the fact of their children studying in bad schools have to see thair children study in awful schools, seeing their families dying in terrible hospitals and living every day of their lives scared about the criminality which the movies represent as something good.
Cazuza was right and I dare repeat his verses: "Brazil! Show your face! I want to see who pays for us to live like that"

Ps= i tried my best to correct the things i found wrong or awkward, there will be some parts which i havent change a thing...that could either be because it was right or i didnt have a better way to rewrite it =) hope i have helped somehow ! btw your text was really good, i couldnt agree more with you!