Order of Items in a Stacked Bar Chart

How can I sort a horizontal stacked bar chart to show the longest stacks on the top?

{
	"dimensions": {
		"Users": {
			"order": "ASC"
		},
		"Tag": {
		},
		"Source": {
		}
	},
	"type": "horizontal-stacked-bar",
	"x": "Users",
	"y": "Tag",
	"color": "Source",
	"plugins": [{
		"name": "tooltip",
		"settings": {}
	}],
	"data": [...]
}