The DropDownList can be programmatically populated in the initialise event using an array of key=value pairs  on the items property . So for your particular example, to populate the list starting at the current year and running for 5 years would look something like:
The above code will add 5 entries to the drop down list
0=2018 Item Name
1=2017 Item Name
4=2014 Item Name
When the item is selected, the keywill be stored in the field property. If you want the valuestored instead, then just leave out the key= part to the item string when you are adding it to the items array.