In a pie chart, the whole 'pie' represents 'all of the data graphed'.
In percent, that's "one hundred per cent", or "one hundred per hundred"
As a fraction, the whole circle represents 100/100, or 1/1 or 1.00 — all of which mean "one whole thing".
Smaller portions are written as fractions of the whole, with the 'whole' fixed at 100 (percent) or 1.00.
So a 20 pence piece represents 20/100 of a pound, which is 20 percent of a pound, or may be written as a decimal as 0.20 pound.
One pound is 1.00 pound, or 100% of a pound.
A 10 pound note is 10.00 pounds, or 1000% of a pound.
And getting into the range of values on your Chart 16, 455 pounds is 455.00 pounds, or 45500% of one pound, which, as you can see, is correctly represented on the chart.
Here's a pair of charts, and the table that feeds them. Same data as in your example, but with the Y axis scale showing the raw data numbers on Chart 1, and the fraction of the total (1146) that each amount represents on the chart 2.
Formatting the Y axis labels to show percent doesnt change the values. The numbers are multiplied by 100, and the % sign is attached to show that these are the number per hundred. For chart 1, where the current scale takes no account of the total, converting to percent doesn't make sense.
For Chart 2, with the current scale, the four bars show (approximately) 0.2, 0.3, 0,4 and 0.1. Altogether, that's 0.2+0.3+0.4+0.1 = 1.0
Converting Chart 2's Y axis values to percents changes the labels on the four non-zero lines to 10, 20, 30 and 40%. The four bars now show 20, 30, 40 and 10 percent. Add those up and you get 100% (which is always the total percentage of 'the whole thing'.
Regards,
Barry