This is an excellent article. I have one confusion regarding excluding population growth effect from the GDP growth. We have assumed that new borne doesn't contribute to the economy till the age of 15years. So we should take out the average population growth for those period of 15years, which is preceding 10 to 25 years. So time scale wise -

1933..............25th year ............10th year .............2011
from 2011 from 2011

Please let me know if I am missing anything.