Benchmarking is a common way to evaluate the effectiveness of finite state machine (FSM) low-power methodologies. The serious problem in the existing standard benchmarks is that power-related characteristics are not provided, and therefore these benchmarks are not complete for reliable evaluation and comparison of low-power methods and tools. To address this problem, this paper introduces the coefficient of variation, which is very useful for quantitative analysis of power-related features of an FSM, and for indicating the power optimization opportunity of the corresponding circuit. Based on the coefficient of variation, input-sensitivity analysis of the whole standard benchmark set is conducted. It reveals that the benchmark set is input-data dependant, and the set is insufficient for low-power FSM researches due to the limited coverage of power-related characteristics.