Consider the following statements regarding the India-Russia Exercise INDRA:
Statement 1: It occurred in two phases, the first one in Chennai and the second one in the Bay of Bengal.
Statement 2: This year's edition was the 15th one.
Statement 3: It was started in 2003, and since then, it has been held once every year.
Statement 4: The exercise grew into a tri-service format, though recent editions emphasize naval cooperation.
Which of the above statements is/are CORRECT?