Barden's Schedule for Rating Performance

I had an interesting query about what defines a "promising" junior player. However it wasn't a query about temperament or skills but something more direct and quantifiable. The question was essentially about the relationship of rating to age, and whether this was a predictor of future success.
The question sparked a memory of something I read in the very excellent "Play Better Chess" by Leonard Barden. Towrds the back of the book Barden had a table of BCF grades and player ages which indicated whether a player would reach 2200 by the age of 23. As I couldn't find it online anywhere I dug up my copy of the book. Here is an abridged version of the table (translated into ELO ratings), with the caveats that it was published in 1980, the translation of BCF to ELO ratings (using the BCF*8+600=FIDE formula) isn't always accurate, and ACF ratings may or may not be 200 points lower than their FIDE equivalents.

• Age -> Rating
• 6 1000
• 7 1160
• 8 1288
• 9 1408
• 10 1512
• 11 1600
• 12 1680
• 13 1760
• 14 1832
• 15 1892
• 16 1948
• 17 2000
• 18 2044
• 19 2084
• 20 2120
• 21 2152
• 22 2176
• 23 2200