I have a bar chart in my report which, on the x-axis, reflects the percentage of all answers which fall into a category, and on the y-axis, reflects the categories:

There are two more categories which are not showing on the y-axis: "Weak" and "Very weak", each of which recieved zero answers, and so have a 0% value.

I still need those two categories to appear on the y-axis, though, and have not been able to make that happen.

EDIT at @R.Richards' request:

The graph is being created by drawing data from this query:

SELECT multiple_choice FROM mytable

...where multiple_choice is a field with values between 1 and 5.

The chart category is multiple_choice , and the values are based on the expression

=Count(Fields!multiple_choice.Value) / Count(Fields!multiple_choice.Value, "ChartName")

FURTHER EDIT following a comment from @iamdave:

As values for the categories "Very Weak" and "Weak" were not selected at all in the dataset, the only place the categories appear is in the Labels - which are created with an expression: