Number letter counts

If the numbers \( 1 \) to \( 5 \) are written out in words: one, two, three, four, five, then there are \( 3+3+5+4+4=19 \) letters used in total.

If all the numbers from \( 1 \) to \( 1000 \) (one thousand) inclusive were written out in words, how many letters would be used?

NOTE: Do not count spaces or hyphens. For example, \( 342 \) (three hundred and forty-two) contains \( 23 \) letters and \( 115 \) (one hundred and fifteen) contains \( 20 \) letters. The use of "and" when writing out numbers is in compliance with British usage.