According to sales data, during the past 35 years the returns for high-end stringed instruments have vastly exceeded the performance of American stocks (see chart).
据销售数据来看，过去35年里，高端弦乐器的回报率远远超过了美国股市的表现(如图)。
2
Connecting with working practice, this paper tries to draw up the quantity value source-tracing chart of the measuring instruments, and puts forward some concrete methods.