You can track the user input on the last field (i.e country)
row1>Id, Name , City ,Country (lost focus 2nd row inserted)
row2>Id, Name , City ,Country (lost focus 3rd row inserted)
row3>Id, Name , City ,Country
Now i am going to change the details of first row ,it will automatically insert new row while new row is already added ,its not good idea to put event-control at the last textbox.
one of the best practice says, create two buttons(eg. Add,Remove)
put hidden counter for number of rows currently added.
If user clicks on the Add button just add new row at the end and remove if he/she clicks on the Remove button.Also you can use Ignore(checkbox) so that if user want to discard middle row and wants to insert data of 1 and 3 rd row.
It's up to ur requirement.
Hope this will help you