title: SSRS Expression to Get last 12 months
body: <p>I have created a ssrs report and this report display last 12 months data. I have 2 parameters startDate and Enddate. 
  The End date is always the current month and I want the start date to be the last 12 months. For example if my (End Date) current month is JAN 2018. I want my start date to be Feb 2017. 
  I have below expression but this give me Jan 2017 date for my start date. </p>
  
  <p>=DateAdd("M", -12,Today())</p>