Economic; The importance of trade and economic interests to the participants is often under estimated; contemporaries viewed Dutch and English support for the Habsburg cause as primarily driven by a desire for access to the Spanish American markets. Modern economics generally assumes a constantly growing market whereas the then dominant theory of Mercantilism viewed it as static. As a result, increasing your share of trade implied taking it from someone else, with the government's role being to restrict foreign competition. Trade was often used as a policy weapon; between 1690-1704, English import duties increased by 400%, while the 1651-1663 Navigation Acts were a major factor in the Anglo-Dutch Wars. On 6 September 1700, France banned the import of English manufactured goods like cloth and imposed prohibitive duties on a wide range of others. Military; the armies engaged in the Nine Years War often exceeded 100,000 men and proved too large for the pre-industrial economies of its participants. Those of 1701-1714 averaged around 35,000 - 50,000 but a dependence on water-borne transport accentuated the importance of rivers like the Rhine in Germany or the Adda in Northern Italy. Reliance on the local countryside for resupply limited operations in poor areas like Northern Spain; these factors confined campaigns to the same general areas.
Question: How many years did the Navigation acts span?
Answer: 2