This isn't a running total, it's just a count of the number of records in each category.
Define a "count of" summary field. It can count any never empty field so you can specify either field 1 or field 2 as the field that it counts. Do NOT select the "running total" option.
Create a new layout based on this table. Set it up for List View.
Remove the Body layout part.
Replace it with a sub summary layout part "when sorted by Field 2".
Put field 1, Field 2 and the summary field in this layout part.
Then sort the records by Field 1 and Field 2 to prodcuce the result that you've specified.
Note: without correct sorting, this layout will be blank.
Perhaps a silly question but is there also a way to put this into a portal so I can add it in a different layout?