Magic numbers Let yo be the GDP per capita at year 0,y the GDP per capita at year T,and x the average annual growth rate over that period Then, y=(1+x)T yo Taking logs,we compute lny灯-lnyo=Tln(1+x)≈Tx, or equivalently x=(In yr-In yo )/T.Magic numbers  Let y0 be the GDP per capita at year 0, yT the GDP per capita at year T , and x the average annual growth rate over that period. Then, yT = (1+ x ) T y0  Taking logs, we compute ln yT - ln y0 = T ln(1+ x) ≈T x, or equivalently x = (ln yT - ln y0 )/T . Chyi, Macro I, 2006