If you were born on Sunday, August 30, 1942 then Alone Again (Naturally) by Gilbert O'Sullivan was the number one on your 30th birthday, and went to number one on August 27, 1972. Check the price of Alone Again (Naturally) by Gilbert O'Sullivan on Amazon.com
The biggest selling book of 1972 (the year you turned 30) was Jonathan Livingston Seagull by Richard Bach.