##  [1] "date"       "hunperm"    "huauthst"   "hustart"    "hucomp"    
##  [6] "huconst"    "permast"    "permst"     "permcomp"   "permcont"  
## [11] "authcomp"   "startconst" "constcomp"  "salall"     "salspec"   
## [16] "salcomp"    "salconst"   "avgsal"     "GDPdai"     "yystarts"  
## [21] "yyhunperm"  "yyhucomp"   "yyhuconst"  "yyhuauthst" "yysalall"  
## [26] "yysalspec"  "yysalconst" "yyavgsal"   "yyGDPdai"   "year"      
## [31] "month"