?????? ???????? ????? ?????? ?????? ????? ?????? ????????????? ?????????????? ??????????? ??? ????? ???????????? clearly show ??????????? ???????? ??????? ?????? 1,600-2,000 ??????? ?????? ??????????? ??? ??????? ??? ????????? ??????? ????? ????????? ?????? ???????????? ??????????? ????????????? ???????????? “??? ???? ??? ??????? 40% ??? ??????