Change in Missionary Age Requirements

Many Latter-day Saints, me included, were excited when President Thomas Monson announced at General Conference that young men could now serve a mission at 18 years of age and young women at 19.  Prior to the announcement, 14% or 8,120 of the 58,000 missionaries were Sisters.  A short time thereafter, the Church issued a statement that reported a 471% jump in missionary applications over a two week period from 700 to 4,000 per week.  My mind began to race.  How many would be added to the 58,000 missionaries serving and how would the composition change between Elders and Sisters?  

Two data points is not enough to forecast the increase in the missionary ranks with any degree of certainty but I had fun thinking about some possibilities.  The linked article stated that a little over half of the applications were from young women.  For ease of calculation, make that 50% or 2,000 applications.  The average number of applicants per week prior to the announcement was 700.  Of that number, approximately 570 applications are from young men, and 130, from young women.  Backing out those numbers from the 4,000 news applications, there was an increase of approximately 1,430 from young men and 1,870 from young women.  That translates to an increase of 151% for young men and 1,130% for young women.  A back of the envelope calculation suggests that about 33% of future missionaries in the field will be young women.  ¹

This number of applicants will not persist.  The new rule doubles the number of young men that come of age to serve and triples the number of young women.  Next year, only one year of each will come of age. Assume that the number of Sisters as a percentage of the missionary stays at 33%.  In a worst case scenario, the number of Elders stays constant.  This implies that the number of Sisters will increase to 19,140 and total missionaries to 67,020.  If the number of Elders increases by 10% or 4,788, to 52,688, the number of Sisters would increase to 21,054.  Total missionaries would jump to 73,722.  Finally, if the number of Elders increased by 20% the missionary force would climb to 80,424. The prophesy of the stone that was cut out to the mountain without hands to roll forth, until it fills the whole earth is a bit closer to being fulfilled. 

1.  After subtracting out the number of applications normally received, from the 2,000 applications from young men and young women, there has been a net increase of approximately 1,430 and 1,870.  Because two new years of applications are coming from young women and only one from young men, divide the applications from young women by 2, making the applications per year 935.  Because Sisters serve for 18 months, multiply the applications from young women by .75 resulting in 701 Sister missionaries to 1,430 Elders.  This implies that 32% of the missionaries serving will be Sisters.