The trade dollar was produced in response to other Western powers, such as Great Britain, Spain, France, and particularly Mexico, to compete with these trade coins for use in trade in Asia. American trade dollars are 90% silver and weigh 420 grains (27.2 g), which is about 0.5 g heavier than the regular circulation Seated Liberty Dollars and Morgan Dollars. Most trade dollars ended up in China during their first two years of production, where they were very successful. Many of them exhibit holes or chopmarks which are counterstamps from Asian merchants to verify the authenticity of the coins. Many trade coins of the western powers and large silver coins from China, Korea, and Japan also bear these chopmarks. While most chopmarked coins are generally worth less than those without, some of the more fascinating chopmarks can actually give the coin a modest premium.