A military power during the 17th century, Sweden has not participated in any war in almost two centuries. An armed neutrality was preserved in both World Wars. Sweden's long-successful economic formula of a capitalist system interlarded with substantial welfare elements has recently been undermined by high unemployment, rising maintenance costs, and a declining position in world markets. Indecision over the country's role in the political and economic integration of Europe caused Sweden not to join the EU until 1995, and to forgo the introduction of the euro in 1999.