Are you referring to Excel for Mac or Win? For example when you refer
to 2.1, it was actually 2.2 for the Mac. This listing you give appears
to be for Windows. They are not the same, particularly after the
formation at Microsoft of the Mac Business Unit which began developing
Office applications with unique features designed for Mac customers and
needs. Most recently for Excel this was Excel X for Mac (for OSX), but
versions prior to that were called Excel 98 and Excel 2001. Perhaps
there is (or should be) an article in the Microsoft Knowledge Base that
would specifically give the history for the Mac.

DRDurham