How to incorp missing years into a timeline line graph Xaxis without the values taken as 0

Hello all, I have a quick query that I would greatly appreciate any help with. I am drawing a line graph to illustrate the overall trends in violence between 1981 and 2012.

However crime data is only available (was only counted) in certain, sporadic, years - aka there is data for violence in 1981, then the next available lot of data is from 1984, then 1988, then 1990, then 1991 etc - so the data I am looking at has been taken at - and is only available for - uneven intervals.

I cannot seem to callibrate the x axis to accomodate the unusual intervals of these crime years. I want appropriate spaces for 'missing' years if that makes any sense.

Currently the line graph spaces the distance between 2001 and 2002 cases equally with the distance between 1984 and 1988 cases etc which I imagine is causing artificially steep peaks and falls in their appearance. I cannot work out how to re-design the x axis to suit these specific needs.

When I try and add empty columns for the missing years - e.g. introducing empty columns for 1985, 1986, 1987 - the line graphs takes these to be values of 0 - and causes the trend line to dip to zero.

The spacing works (leaving empty year columns) when drawing scatter plot diagrams which is what I am currently using, but I am desperate to create line graphs for publications etc.

Thanks for reading.

Thanks to you both,
yes both of those options work, I am slightly embarassed as to how obvious that was afterall!