The country A Consumer Price Index is approximated by the following formula, where t represents the number of years after 1990. A(t)=100e^0.021t For instance, since A(16) is about 140, the amount of goods that could be purchased for $100 in 1990 cost about $140 in 2006. Use the function to determine the year during which costs will be 70% higher than in 1990.