Looking for a report that would give me each customers sales for a year and the % that customer is of the overall.  Does any such thing exist?

Right. And because you will be pulling a significant amount of data from multiple tables and then collating that and turning it into a one-line-per-customer report, Access would be the easiest toolset to work with to get that. Unless you are really good and comfortable with Crystal. Would be a pretty big pain in the ass to do in Excel.

I will manually calculate the % for now.  
 
I am not familiar with access or crystal or the TAS6 report stuff...
 
I bought access to begin learning it but I'm not even sure if I start in access and pick from DBA or vice versa.
 
Oh those beginners...

Let me send you a new RTM, the old one had the total field sizes too small.

Actually, I posted the RTM to www.istechsupport.com/dl/topsale.zip so anybody can download it.  Unzip to DBAMFG and then use SA-M and call out that RTM.

Like Tim said, Data Export to spreadsheet.
 
First you have to run the BKCVUTIL (UT-A, or someplace on the menu) - select Customers and both years.
Then export data from BKARCUST (DE-A) to a delimited text file. Select whatever fields you want, but probably BKAR.CUSTCODE, BKAR.CUSTNAME and BKAR.GROSS.LYR.
 
Then open it in your spreadsheet, add a couple very simple formulas (one grand total, and then customer total divided by grand total, format as a percentage) and there you are.
 
You can also do the same type of thing for Vendor purchases.