My salary and my retirement savings grew at different rates. My retirement savings grew from $0 in the first year to $384,000 in the 30th year. My salary grew from $57,636 to $118,000 at a 2.5% rate in 30 years. As my salary increased, my savings grew because I had some money that I could put aside into my retirement savings account. Once I saved enough money, I decided to put a bit more money yearly into my retirement savings. In the first year, the amount I put in was $2881. Over a period of 30 years, the amount I put in nearly doubled to $5897. Part of the magic of compound interest is that in this case, after 12 years, the amount of money I get back is more than the amount of money that I put in.