First thing you'd need to do is to reshape your data so that there is one type per row, rather than all the types being on the same row. This is pretty easy with just the one row, if your data has many rows, i.e. per department or something, you may want to use the Tableau excel Add in
Secondly, you'll need to change the numbers when there is a reduction in staff so that it is negative.
Now you can connect to the data in Tableau.
Put Type on Columns and the actuals on Rows, and make the Actuals measure a running total. Filter out the Ending Headcount type, and turn on Row grand totals instead. Change to a Gantt and create a new calculated field with the formula -[Actuals] and put that on size. You should now have the basic shape and can add colour if needed.
See the attached for an example, and see the video here for a walkthru... Waterfall Charts | Tableau Software
Sample Data_Waterfall.twbx.zip 39.0 KB
Thanks Robin, it worked.