We examine the relative importance of the growth of physical and human capital and the growth of total factor productivity (TFP) using newly organized data on 145 countries that spans more than 100 years for 23 of these countries. For all countries, only 14% of average output growth per worker is associated with TFP growth. We use priors from theories to construct estimates of the relative importance of the variances of aggregate input growth and TFP growth across countries. Much of the importance of the variance of TFP growth across countries is associated with negative TFP growth. (JEL O47, O50, O57, O30, N10)