???

??????????????????2?4-10?????2-3????



1



?,95%???????????????5%?????????????????????Y??????????????????



2



1?????????????????50-60%



2????????????????30%



3???????????????10%?

4???



5??????



6????????



3?



1????



????????5-10??????????????????????



??????????????????1-2????



????????????????????6-12???????



??????????@????????@?



???????????????????
2?????????????????????



4



1??????????????



2??????????????



3X???X?????

5?



1?????



??????12????24????...