The above graph shows for Great Britain (England & Wales - to be a little more precise) the values of lowest denomination coin, higest denomination coin, lowest denomination note and higest denomination note. Each value has been corrected for the retail price index (R.P.I.). I used the R.P.I. for the June of each year 1965 thru’ 2000 as found on the page  http://www.wolfbane.com/rpi.htm .  The scale I have used on the Pounds axis is scaled logarithmically - otherwise things just would not fit !

Notice how our 1 Penny coin is worth as little now as the decimal half penny was worth when it was denometised (see “Low Coin” for 1984 and for 2000). Notice how the 50 Pence had more buying power when first introduced than our 2 Pounds coin did when it was first introduced (see “High Coin” for 1969 and for 1997).

I wonder what graphs for other countries would look like !