Try this solution:
1. Insert the row outside the group below
2. Add new parent row group within the new row.
3. Add Year field from your dataset as your grouping element
4. When the new group is created go to properties of this group
5. Go to "Filters" tab and add new filter
6. In "expression" field choose Year, in "value" field insert value of "2012"
7. Repeat this for year 2013.
In design mode your report should look like this: