How to get the timestamp for Set state on an object through API?

Lifecycle history table displays the action, actor name, date in Routing history tab.
Action and actor name are obtained through the following code.

QueryResult LCHistoryList =LifeCycleHelper.service.getHistory((LifeCycleManaged) epm);

if(LCHistoryList.hasMoreElements())

  {

   LifeCycleHistory lct=(LifeCycleHistory)LCHistoryList.nextElement();

   String action=lct.getAction();

   String actorName=lct.getActorName();

   Timestamp createDate =lct.getCreateTimeStamp();

  }

Timestamp object createDate fetched is always null.

Can you please help me how to fetch the timestamp from LifeCycleHistory object?