stata 数据总是显示时间面板重复

数据显示时间面板重复使用设置面板数据后，出现”repeated time values within panel“，然后使用了 duplicates drop year, force语句，但是我的观测值被删得只剩下了6个，该怎么办呢？继续用下去，相关分析结果不显著，请问是那一步出错了呢？

. import excel "D:\论文数据\数据.xlsx", sheet("Sheet1") firstrow
(12 vars, 1,048,575 obs)

. encode id, gen(id_n)

. label drop _all

. tsset id_n year
repeated time values within panel
r(451);

. duplicates drop year, force

Duplicates in terms of year

(1,048,564 observations deleted)

.
. tsset year

Time variable: year, 2011 to 2020
        Delta: 1 unit