According to Robert Rosen in the 1960s, holistic biology had become passé by the early 20th century, as more empirical science dominated by molecular chemistry had become popular. Echoing him forty years later in 2006 Kling writes that the success of molecular biology throughout the 20th century had suppressed holistic computational methods. By 2011 the National Institute of Health had made grant money available to support over ten systems biology centers in the United States, but by 2012 Hunter writes that systems biology had not lived up to the hype, having promised more than it achieved, which had caused it to become a somewhat minor field with few practical applications. Nonetheless, proponents hoped that it might once prove more useful in the future.