just in case you aren't sure how to proceed (previous posts were rather desperate):
download the data i sent to new folder
rename the excel file and the excel sheet so that it doesn't contain spaces or other weird symbols. just use letters, numbers and "_"
open arcmap
button add data - select shapefile 'colorado counties'
button add data - select 'local crime...' excel file - the first sheet
you should see the colorado counties as polygons. right click in table of content, - open table
in left upper corner button - menu - add field, name it X and type = float
again add field, name it Y and type= float
again add field, name it "name_short" or similar
in table view, right click X - calculate geometry - x centroid
in table view, right click Y - calculate geometry - Y centroid
in table view, right click "name-short" field, - calculate field: vb script fill in: Left( [Name], (Len( [Name] )-7 )) - this will result in a field with only "pueblo" as name rather than pueblo county
in arcmap tabel of content: rightclick your excel table - join - use colorado counties name short and excele sheet name field to join.
right click tabl in table of content - display x y data, using x and y fields which you can select.
voila: one point for every county every year with data appended.
you could also choose to append the table data to the shapefile of county polygons - prettier pictures
remember though there is one polygon per county and there is a large number of county/year records.