差幅 meaning in Chinese

spread

During the period september to november 2003 , there were a total of 3 , 500 cases of statutorily notifiable diseases reported to the department of health ( dh ) , affecting 4 , 108 persons . the number was lower than those of the corresponding period of the previous three years by 17 per cent to 44 per cent
（一）于二三年九月至十一月期间， ?生署接报的法定须呈报传染病个案共有三千五百宗，受影响人数为四千一百零八人，数字比过往三年同期为低，差幅为百分之十七至百分之四十四。