C++ What is the best way of allowing moving data out of a class member (std::move syntax)

Imagine that I have a class whose main responsibility is to populate a data container. I would like to move the data out of this class. So I have:

class cCreator
{  
public: 
   void generate()
   {
      ///generate the content of data_ and populate it
      ....
      ....
   }

   //variation 1
   std::vector<int>&& getData1()
   {
      return std::move(data_);
   }

   //variation 2
   std::vector<int> getData2()
   {
      return std::move(data_);    
   }
private:
      std::vector<int> data_
};

S what is the difference between variation 1 and variation 2 of getData(). What changes when I omit && from the function definition??