Hello Ryan,

You can accomplish this by changing the brush for the x-axis major lines to be transparent:

                    axes: [{
                        name: "xAxis",
                        type: "numericX",
                        interval: 10,
                        title: "Year",
                        majorStroke: "rgba(0,0,0,0)"
                    }

For more information on how to manipulate chart elements like this I recommend checking out our Chart Elements sample and our Configurable Visual Elements documentation. Please let me know if you have any other questions or concerns that I may help with.