如何设置两个X轴

描述:当前是关于Echarts图表中的 柱状图 示例。
 
            option = {
    color: ["#057bff", "#05c7ff"],
    title: {
        text: "泊位周转率利用率",
        textStyle: {
            color: "#81add6",
            fontSize: 16,
            fontWeight: 500
        },
        left: 15,
        top: 10
    },
    tooltip: {
        trigger: "axis",
        axisPointer: {
            type: "cross",
            crossStyle: {
                color: "#999"
            }
        }
    },
    grid: {
        width: '50%',
        height: '70%',
        left: '35%',
        top: '20%'
    },
    legend: {
        orient: 'vertical',
        right: "2%",
        top: "right",
        itemWidth: 15,
        itemHeight: 15,
        itemGap: 15,
        textStyle: {
            fontSize: 14,
            color: "#05c7ff"
        },
        data: ["周转率", "利用率"]
    },
    xAxis: [{
            type: 'value',
            boundaryGap: [0, 0.01],
            name: '%',
            max: 100,
            axisLine: {
                lineStyle: {
                    color: '#6a9ab2',
                    opacity: 0.5
                }
            },
            axisTick: {
                show: false
            },
            splitLine: {
                lineStyle: {
                    opacity: 0.5
                }
            }
        },
        {
            type: 'value',
            name: '/次',
            min: 0,
            max: 1,
            interval: 0.2,
            axisLabel: {
                formatter: '{value} 次'
            },
            axisLine: {
                lineStyle: {
                    color: '#6a9ab2',
                    opacity: 0.5
                }
            },
            axisTick: {
                show: false
            },
            axisLabel: {
                show: true
            },
            splitLine: {
                lineStyle: {
                    opacity: 0.5
                }
            }
        },
    ],
    yAxis: {
        type: 'category',
        data: ['12-15', '12-16', '12-17', '12-18', '12-19', '12-20', '12-21'],
        axisLine: {
            lineStyle: {
                color: '#6a9ab2'
            }
        },
        axisTick: {
            show: false
        }
    },
    series: [{
            name: '周转率',
            type: 'bar',
            data: [0.8, 1.2, 0.9, 1.3, 1.1],
            barGap: '0',
            barWidth: '15',
            itemStyle: {
                barBorderRadius: 15
            },
            xAxisIndex: 1
        },
        {
            name: '利用率',
            type: 'bar',
            data: [53, 45, 35, 58, 41],
            barGap: '0',
            barWidth: '15',
            itemStyle: {
                barBorderRadius: 15
            },
            xAxisIndex: 0
        }
    ]
};