Deneb x-axis

Helly everyone,

I try to recreate a Deneb visual with images of the Batman logos, made by Kerry Kolosko. I have the following Deneb code: 

{
"$schema": "https://vega.github.io/schema/vega-lite/v5.json",
"usermeta": {
"deneb": {
"build": "1.1.0.0",
"metaVersion": 1,
"provider": "vegaLite",
"providerVersion": "5.2.0"
},
"interactivity": {
"tooltip": true,
"contextMenu": true,
"selection": false,
"dataPointLimit": 50
},
"dataset": [
{
"key": "Year",
"name": "Year",
"description": "",
"type": "dateTime",
"kind": "column"
},
{
"key": "Logo",
"name": "Logo",
"description": "",
"type": "text",
"kind": "Image"
},
{
"key": "SampleData",
"name": "Order (Y)",
"description": "",
"type": "quantitative",
"kind": "column"
}
]
},
"config": {
"autosize": {
"type": "fit",
"contains": "padding"
}
},
"data": {"name": "dataset"},
"mark": {
"type": "image",
"width": 75,
"height": 50,
"tooltip": false
},
"encoding": {
"x": {
"field": "Year",
"type": "quantitative",
"axis": {
"titleFontSize": 20,
"labelFontSize": 16,
"title": null,
"grid": true,
"gridColor": "#808080",
"format": ".0f",
"ticks": true,
"tickMinStep": 4 //doesn't not respond
},
"scale": {
"domain": [1939, 1966] 
}
},
"y": {
"field": "SampleData",
"type": "quantitative",
"axis": null
},
"url": {
"field": "Logo",
"type": "nominal"
}
}
}

On the x-axis, I would like to have intervals of 4 years, so 1940, 1944, 1948, etc. It looks like TickMinStep doesn't respond, since the visual only shows 1940, 1950 and 1960 (which is the default I guess). I don't understand why it doesn't respond and how to solve it. I really hope someone does know the answer to it. 

The Excel-file can be downloaded here