@c  -A, --average          report average posting amount

To see the running total changed to a running average, use
@option{-A}.  The final posting's total will be the overall
average of all displayed postings.  The works in conjunction with
period reporting, so that you can see your monthly average expenses
with:

@example
ledger -AM  reg ^expenses:food
ledger -AMn reg ^expenses
@end example

This works in the balance report too:

@example
ledger -AM  bal ^expenses:food
ledger -AMs bal ^expenses
@end example

@c  -D, --deviation        report deviation from the average

The @option{-D} option changes the running average into a deviation
from the running average.  This only makes sense in the register
report, however.

@example
ledger -DM reg ^expenses:food
@end example

@c  -%, --percentage       report balance totals as a percentile of the parent

In the balance report only, @option{-%} changes the reported totals
into a percentage of the parent account.  This kind of report is
confusing if negative amounts are involved, and doesn't work at all if
multiple commodities occur in an account's history.  It has a somewhat
limited usefulness, therefore, but in certain cases it can be handy,
such as reviewing overall expenses:

@example
ledger -%s -S T bal ^expenses
@end example