调整列的宽度echarts 柱状配置项内容和展示

在stack:'total'的情况下设置barWidth无法调整列的宽度，那要怎么样才能调整列的宽度

      option = {
    legend: {
        y: 'bottom',
        data: ['表扬', '咨询查询', '意见', '建议', '投诉', '举报']
    },
    color: ["#F79646", "#4BACC6", "#8064A2", "#9BBB59", "#C0504D", "#4F81BD"],
    xAxis: [{
        axisLine: {
            show: false
        },
        type: 'category',
        splitLine: {
            show: false
        },
        data: ['2017/5/12', '2017/5/12', '2017/5/12', '2017/5/12', '2017/5/12', '2017/5/12', '2017/5/12']
    }],
    tooltip: {
        formatter: "{b}: <br/>{a}: {c}",
        trigger: "item"
    },
    yAxis: [{
        axisLine: {
            show: false
        },
        type: 'value'
    }],
    series: [{
        name: '表扬',
        type: 'bar',
        stack: 'total',
        barWidth: 40,
        data: [80, 180, 280, 380, 480, 580, 680]
    }, {
        name: '咨询查询',
        type: 'bar',
        stack: 'total',
        data: [80, 180, 280, 380, 480, 580, 680]
    }, {
        name: '意见',
        type: 'bar',
        stack: 'total',
        data: [80, 180, 280, 380, 480, 580, 680]
    }, {
        name: '建议',
        type: 'bar',
        stack: 'total',
        data: [80, 180, 280, 380, 480, 580, 680]
    }, {
        name: '投诉',
        type: 'bar',
        stack: 'total',
        data: [80, 180, 280, 380, 480, 580, 680]
    }, {
        name: '举报',
        type: 'bar',
        stack: 'total',
        data: [80, 180, 280, 380, 480, 580, 680]
    }]
};