Here is a chart I made. Hope you find it useful. The numbers are approximate and it depends on your exact method of calculation. I use percentages because that information is easier to find or calculate. This chart is the average percentage using the center frequency (I also have numbers related to each band edge). A lot of people quote a "good" or "well designed" or "average" antenna as having about 10% bandwidth, but it varies a LOT with the exact antenna type in use. The "notoriously wide" bands are 160M, 80M, 10M (despite the smaller numbers), and I would add 6M and 70Cm.
160M 10.55%
80M 13.39%
60M 1.36%
40M 4.2%
30M .49%
20M 2.47%
17M .55%
15M 2.12%
12M .4%
10M 5.9%
6M 7.7%
2M 2.74%
1.75M 2.7%
70Cm 6.9%
33Cm 2.84%
23Cm 4.73%
