For use with {{bar box}}. Can display up to three bars stacked on each other. For instance, this code:

{{bar box
|float=left
|width=200px
|bars=
{{Bar stacked|January|(---)|red|3|blue|27}}
{{Bar stacked|February|+25%|red|8|blue|32}}
{{Bar stacked|March|+10%|red|19|blue|21|green|4}}
}}

Produces this bar box:

January
(---)
February
+25%
March
+10%