Hi, very very very beginner user here. I'm trying to linearly interpolate some missing values but am having difficulties when the missing variable is the first or last. I'm working with country-year so my data looks like this
Portugal Exp per student
1998
1999 27.0
2000 25.8
2001 26.2
2002 23.8
2003 24.8
2004 22.0
2005 25.3
2006 26.8
2007 32.1
2008 25.5
2009 29.2
2010 30.0
2011 26.9
2012
2013 25.1
2014 26.9
2015 26.9
When I use the interpolate function it generates a value for 2012, but not for 1998. I think I understand why this is, but I'm wondering if there is any other way to fill in the missing data? Thanks in advance..