BarChart全体の幅を、変更したい【Flutter】

BarChart全体の幅を変更したいです。(棒グラフ1本1本でなく、全体幅です????)

解決策を教えて頂けると嬉しいです。

以下、検証コードです。

Flutter
1                    Container(
2                      height: 180,
3                      child: BarChart(
4                        BarChartData(
5                          alignment: BarChartAlignment.spaceEvenly,
6                          maxY: 20,
7                          backgroundColor: Colors.black,
8                          titlesData: FlTitlesData(
9                            show: true,
10                            bottomTitles: SideTitles(
11                              showTitles: true,
12                              textStyle: TextStyle(
13                                color: Colors.greenAccent,
14                              ),
15                              margin: 20,
16                              getTitles: (double value) {
17                                switch(value.toInt()) {
18                                  case 0:
19                                    return '14';
20                                  case 1:
21                                    return '';
22                                  case 2:
23                                    return '16';
24                                  case 3:
25                                    return '';
26                                  case 4:
27                                    return '18';
28                                  case 5:
29                                    return '';
30                                  case 6:
31                                    return '20';
32                                  default:
33                                    return '';
34                                }
35                              }
36                            ),
37                            leftTitles: SideTitles(showTitles: false),
38                          ),
39                          borderData: FlBorderData(
40                            show: true,
41                            border: Border.all(
42                              color: Colors.greenAccent,
43                              width: 3,
44                            )
45                          ),
46                          barGroups: [
47                            BarChartGroupData(
48                                x: 0,
49                                barRods: [BarChartRodData(y: 14, color: Colors.orange)]
50                            ),
51                            BarChartGroupData(
52                                x: 1,
53                                barRods: [BarChartRodData(y: 8, color: Colors.orange)]
54                            ),
55                            BarChartGroupData(
56                                x: 2,
57                                barRods: [BarChartRodData(y: 4, color: Colors.orange)]
58                            ),
59                            BarChartGroupData(
60                                x: 3,
61                                barRods: [BarChartRodData(y: 16, color: Colors.orange)]
62                            ),
63                            BarChartGroupData(
64                                x: 4,
65                                barRods: [BarChartRodData(y: 8, color: Colors.orange)]
66                            ),
67                            BarChartGroupData(
68                                x: 5,
69                                barRods: [BarChartRodData(y: 17, color: Colors.orange)]
70                            ),
71                            BarChartGroupData(
72                                x: 6,
73                                barRods: [BarChartRodData(y: 8, color: Colors.orange)]
74                            ),
75                            BarChartGroupData(
76                                x: 7,
77                                barRods: [BarChartRodData(y: 8, color: Colors.orange)]
78                            ),
79                          ]
80                        )
81                      ),
82                    ),
83