What percent of tax should pay to the government, is decided by whom?

i think let me say littel thing about tax before ansewring this question, Tax is

A fee charged ("levied") by a government on a product, income, or activity. If tax is levied directly on personal or corporate income, then it is a direct tax. If tax is levied on the price of a good or service, then it is called an indirect tax. The purpose of taxation is to finance government expenditure. One of the most important uses of taxes is to finance public goods and services, such as street lighting and street cleaning. Since public goods and services do not allow a non-payer to be excluded, or allow exclusion by a consumer, there cannot be a market in the good or service, and so they need to be provided by the government or a quasi-government agency, which tend to finance themselves largely through taxes.Read more:http://www.investorwords.com/4879/tax.html#ixzz4IVo4RFva;

So the collected amount and the rate is decide by the government after considering the revenu to be gained from public and the plan that the government expenditure trhou out tax period.