SALT LAKE CITY - The historic increase in Mormon missionaries last year didn't lead to an immediate spike in converts, but church officials say it's too early to draw conclusions.

After lowering the minimum age for missionaries, the number of proselytizing members of The Church of Jesus Christ of Latter-day Saints increased by 41 percent in 2013, show figures released earlier this month from the Salt Lake City-based faith. The number of converts, however, only increased by 4 percent last year.

That means the average number of people converted per missionary, per year, dropped to 3.5 last year - down from an average of 5 the previous decade, said Matt Martinich, a member of the LDS church who analyzes membership numbers with the nonprofit Cumorah Foundation.

"It shows a pretty stark decline," said Martinich, while adding that it will take at least one more year of data to accurately assess the impacts.

The story was first reported by The Salt Lake Tribune.

Church leaders said it's problematic to draw conclusions about the impact of the increase in missionaries based on comparing conversion numbers from 2013 to the year. Much of last year was spent ramping up to be ready for the increase, they said. It was a major undertaking to get thousands of young men and women trained for their missions, get staff for 58 new missions created and to set existing missions for more missionaries, said church spokesman Eric Hawkins.

"Implementing something as large as this and seeing results takes time - perhaps years," Hawkins said.