?????? ???? 0.43%? ?? ?? ??? ???(0.31%) ???(0.07%) ???(―0.11%)? ?? ???.

?????? ??? ? ????? ??? ??? ??1??? ??????? ??? ????2,3, 4??, ???? ??? ???? 500?～1500??? ??? ???. ????2?? 16??? 4?7000?～4?8000??, ???? 19??? 5?7000?～5?9000??? ???.

?????? 1979?? 80?? ??? ??? ??, ??? ??????? ?? ???. ??? ??? ???? ??? ???? ?? ??? ??? ????? ??. ???? 34??? 500?? ?? 5?5000?～5?7000??, ????1?? 11??? 1000?? ?? 2?3500?～2?4000??.

?????? ???? ????? 0.27%? ?? ?? ???. ?? ???? 2008? ?? ??? ??? 9??? ??? ???, ??? ??? ??? ??? ??.

?????? ???·???(0.22%) ???(0.20%) ???(0.12%) ????.

???????? ??(0.22%)? ??? 7?? ??? ?? ????? ?? ???? ??? ?? ???? ??? ?????? ??(0.31%) ??(0.29%) ??(0.21%) ??·??(0.18%) ?? ?? ???.