Schoenherr and his colleagues collected data on priestly ordinations, resignations, migration, retirement, and mortality from 1966 to 1984 in 86 randomly selected U.S. dioceses. Analysis of this data revealed the number of priests in the United States declined by almost 20% between 1966 and 1984. Schoenherr's team projected that for the next twenty years the population of ordained priests will decline in number and increase in average age. The projections ranged from an optimistic 34% decline to a pessimistic projection of a 53% decline. A third projection, based upon the moderate assumption that the trends observed in the early and mid-1980s will continue, forecast a 40% decline in the number of priests. The researchers discovered that while New England dioceses will experience the most severe decline in numbers of priests and some Southern dioceses will see the least decline, differing rates of Catholic population growth suggest that most regions will experience a significant increase in the ratio of lay persons to priests. They also concluded that recruitment failures were more significant factors in the decline in the priest population than retention problems.