According to About.com, the value of $1 in 2014 currency would have been worth $5.92 in 1970. The value of a dollar today is worth less than it was in the past due to inflation. To offer further perspective, that same dollar was worth $23.63 in 1913.
According to About.com, the Federal Reserve targets a core annual inflation rate of 2 percent. In other words, as long as prices only go up 2 percent per year, the economy should continue to grow at a healthy rate. This also means that just to keep up with inflation, average salaries need to increase by an average of 2 percent per year, as well.