各位前辈，我想用name进行分组，求zhi的增长率，结果如最右列所示，不知道如何操作呢？数据如下。

[CODE]
* Example generated by -dataex-. To install: ssc install dataex
clear
input str5 var20 str4 var21 str3 var22 str8 var23
"name"  "year" "zhi" "jieuo"   
"00001" "2008" "4"   ""        
"00001" "2009" "2"   "=(2-4)/4"
"00001" "2010" "3"   "=(3-2)/2"
"00002" "2008" "2"   ""        
"00002" "2009" "3"   "=(3-2)/2"
"00002" "2010" "6"   "=(6-3)/3"
"00003" "2008" "5"   ""        
"00003" "2009" "4"   "=(4-5)/5"
"00003" "2010" "3"   "=(3-4)/3"