Index returned while invoking handler specified for "watch" on KV store

As a part of “watch” on a kv store, the handler is invoked by passing an index and a json data. On initial inspection I noticed that this index is incremented after each operation.
Suppose we have two operations on kv store o1 and o2(o2 happens after o1)
The handler will be invoked 2 times.
In the handler we receive idx1, idx2 as indices for operations o1 and o2 respectively.
My question is will idx2 will always be greater than idx1?