i have panel data of firms. i have merged two data sets to process data further first i tired to declare it as panel. unfortunately, stata issued an error message. the code and error message is as:
xtset gvkey year
repeated time values within panel
r(451);

however, i have checked past posts. i also tried commands suggested in these post but none solved the problem. my data consists of 3698 firms, 30 variables, 69018 observations from year 1992 to 2016.
my data set of gvkey and year is as:
1004 1992
1004 1993
1004 1994
1004 1995
1004 1996
1004 1997
1004 1998
1004 1999
1004 2000
1004 2001
1004 2002
1004 2003
1004 2004
1004 2005
1004 2006
1004 2007
1004 2008
1004 2009
1004 2010
1004 2011
1004 2012
1004 2013
1004 2014
1004 2015
1004 2016
1013 1992
1013 1993
1013 1994
1013 1995
1013 1996
1013 1997
1013 1998
1013 1999
1013 2000
1013 2001
1013 2002
1013 2003
1013 2004
1013 2005
1013 2006
1013 2007
1013 2008
1013 2009
1013 2010
1034 1992
1034 1993
1034 1994
1034 1995
1034 1996
1034 1997
1034 1998
1034 1999
1034 2000
1034 2001
1034 2002
1034 2003
1034 2004
1034 2005
1034 2006
1034 2007
1045 1992
1045 1993
1045 1994
1045 1995
1045 1996
1045 1997
1045 1998
1045 1999
1045 2000
1045 2001
1045 2002
1045 2003
1045 2004
1045 2005
1045 2006
1045 2007
1045 2008
1045 2009
1045 2010
1045 2011
1045 2012
1045 2013
1045 2014
1045 2015
1045 2016
1055 1992
1055 1993
1055 1994
1055 1995
1055 1996
1056 1992
1056 1993
1056 1994
1056 1995
1056 1996
1056 1997
1056 1998
1056 1999
1056 2000
1056 2001