My retirement fund starts lower than my income but grows at a faster rate. There are two reasons for this. The first is that my income grows at a rate of 2.5% annually while my interest rate on my retirement fund is 7.1% annually. The second reason is that the interest earned is a percentage of my invested money. When my income goes up, the amount of money I invest goes up as well. Since there is more money, the value of the percentage goes up as well, and therefore earning me more money. At the end of the 14th year investing, the value of my investments exceed my annual income. Nine years later, at the end of year 23, the value of my investments will be more than double my annual income.