The DE30 is a capitalization-weighted index made up of 30 of the largest and most liquid German companies listed on the Frankfurt Stock Exchange. The Germany 30 formerly known as Deutscher Aktien IndeX(DAX) 30 was introduced on 30 December 1987 at a base value of 1000. It is often likened to the Dow Jones Industrial Average (DJIA) in the U.S. and is considered as one of the most important indices for European investors. The index is viewed as a good indicator of the German economy and investor sentiment towards German equities. Recent estimates have revealed that GDAXI member companies earn about 75% of sales from abroad making it necessary for international traders to watch the performance of the index. The index's weightings are based on market capitalization and order book volume, and the constituents are reviewed quarterly. Among the companies listed on the German 30 Index include BMW, Siemens, Adidas and Deutsche Bank.