See https://github.com/adamcooke/vat-rates and http://www.vatlive.com/vat-rates/european-vat-rates/eu-vat-rates/

proposed-vat-json-format.json

{
	"url": "http://example.com/json",
	"rates": [
		{
			"name": "Belgium",
			"code": "BE",
			"periods": [
				{
					"effective_from": "1996-01-01",
					"rates": {
						"standard": 21.0 ,
						"reduced": [
							{
								"value": 12.0,
								"types": [
									"restaurants"
								]
							},
							{
								"value": 6.0,
								"types": [
									"books",
									"cultural events",
									"entertainment events",
									"hotels",
									"foodstuffs",
									"medical",
									"newspapers",
									"pharmaceuticals",
									"water"
								]
							}
						]
					}
				}
			]
		},
		{
			"name": "France",
			"code": "FR",
			"periods": [
				{
					"effective_from": "2014-01-01",
					"rates": {
						"standard": 20.0 ,
						"reduced": [
							{
								"value": 10.0,
								"types": [
									"accommodation",
									"cultural events",
									"entertainment events",
									"hotels",
									"passenger transport",
									"pharmaceuticals",
									"restaurants",
									"sporting events"
								]
							},
							{
								"value": 5.5,
								"types": [
									"books",
									"ebooks",
									"foodstuffs",
									"medical"
								]
							},
							{
								"value": 2.1,
								"types": [
									"newspapers",
									"pharmaceuticals"
								]
							}
						]
					}
				}
			]
		},
	]
}

Maybe types could either have strings for cases without exceptions or objects/hashes if there are any special conditions