code: public com.google.api.ads.adwords.axis.v201809.cm.EfficiencyTargetType getEfficiencyTargetType() {
          return efficiencyTargetType;
      }
docs: Gets the efficiencyTargetType value for this PerformanceTarget.
  
  @return efficiencyTargetType   * This property specifies desired outcomes for some clicks, conversions
  or impressions
  statistic for the given time period. It's usually
  a constraint on the volume goal of the
  performance target, usually in terms of spending.
  
  <p>Only specific efficiency target types are allowed
  for a volume goal type. The following
  mapping explicitly specifies all allowed combinations.
  Volume Goal Type : List of Efficiency Target Types
  MAXIMIZE_CLICKS : CPC_LESS_THAN_OR_EQUAL_TO
  MAXIMIZE_CONVERSIONS : CPA_LESS_THAN_OR_EQUAL_TO
  <span class="constraint Selectable">This field can
  be selected using the value "EfficiencyTargetType".</span><span class="constraint
  Filterable">This field can be filtered on.</span>