## [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"