RM Retention Comparative Statistics?

[_sock puppet]

Does anyone know if there has been a statistical study comparing the retention rates of returned missionaries (RMs) with those that were temple married by age 23 and neither served a mission or married an RM? That comparison should show the real effect of serving a mission on LDS retention rather than comparing them against all raised LDS, many of whom had serious doubts if they had not already left the LDS reservation before getting near mission eligibility age.