interest on it. Although this scheme was a profitable enterprise for the government as well as the publicani, it was later replaced by a direct tax system by the emperor Augustus; after which, each province was obliged to pay 1% tax on wealth and a flat rate on each adult. This brought about regular census and shifted the tax system more towards taxing an individual's income rather than wealth. Islamic rulers imposed Zakat (a tax on Muslims) and Jizya (a poll tax on conquered non-Muslims). In India this practice began in the 11th century. Trends Numerous records of government tax collection in Europe since at least the 17th century are still available today. But taxation levels are hard to compare to the size and flow of the economy since production numbers are not as readily available. Government expenditures and revenue in France during the 17th century went from about 24.30 million livres in 1600–10 to about 126.86 million livres in 1650–59 to about 117.99 million livres in 1700–10 when government debt had reached 1.6 billion livres. In 1780–89, it reached 421.50 million livres. Taxation as a percentage of production of final goods may have reached 15–20% during the 17th century in places such as France, the Netherlands, and Scandinavia. During the war-filled years of the eighteenth and early nineteenth century, tax rates in Europe increased dramatically as war became more expensive and governments became more centralized and adept at gathering taxes. This increase was greatest in England, Peter Mathias and Patrick O'Brien found that the tax burden increased by 85% over this period. Another study confirmed this number, finding that per capita tax revenues had grown almost sixfold over the eighteenth century, but that steady economic growth had made the real burden on each individual only double over this period before the industrial revolution. Effective tax rates were higher in Britain than France in the years before the French Revolution, twice in per capita income comparison, but they were mostly placed on international trade. In France, taxes were lower but the burden was mainly on landowners, individuals, and internal trade and thus created far more resentment. Taxation as a percentage of GDP 2016 was 45.9% in Denmark, 45.3% in France, 33.2% in the United Kingdom, 26% in the United States, and among all OECD members an average of 34.3%. Forms In monetary economies prior to fiat banking, a critical form