This here I totally agree. I am thankful that I got all my job offers through this channel and have to admit the pay has been satisfying. Get your CVs to reputable agents and one day you might get a call with an opportunity that is difficult to turn down.
I will not share my current salary here as I don't want to brag, but I am very much thankful for what I am getting.
I am still at Engineer level, though. Not yet senior, mind you. But I earn enough to sustain my family (but we don't live lavishly, though. We save for our future).

even if i don't reveal my salary, there is nothing to lose in submitting your CV to good agents. once they have you in their database, they will contact you when a suitable posting appear, even though you don't apply or you don't even know it's there. if they don't contact you right away, it is usually because there is no position... this is how good agents work, they don't simply shoot CVs here and there hoping one will succeed.
my first experience with agents was in 2008; though I submitted my CV in 2006, I only got contacted by their UK office in 2008. the next few jobs i have, i also didn't actively apply but was contacted by the agents for a suitable posting.

12% upon confirmation is very good. 5% per annum increase is also quite good. But… Everything is relative. What is good to some, may not be good for others. It may be good to compare once in a while, but you shouldn’t really be encouraged/discouraged by how people are doing.

What is really important, is: “are you getting enough?”

When you think about it, some people don’t need double digit increment per year (5% is already good enough for them). As long as they can have a good saving and their total living cost is low, they can withstand that level of increment.

For example, say someone is earning net salary of 10k per month. The total living cost is 5k and inflation is 6%. In a simplified calculation, his/her living cost would be 5.3k by end of the year, an increase of 300 - which is effectively just 3% of his/her salary. So if he’s getting 5% increment, such a person is already better off. But if the total living cost is 9.5k, the same numbers would result in “new” living cost of 10,070 and salary of 10,500 (saving is actually decreased from 500 to 430 – before even taking inflation into consideration).

But these are just overly simplified examples using inflation as a benchmark. I'm just trying to demonstrate two scenarios where the numbers are the same but resulting differently. I'd advise person No. 2 to nego for higher increment or get a new job.

For me, at the end of the day, I compare how much I save before and after an increment (I have quite a detailed monthly expenditure records to do this – so I don’t really use inflation number). If I end up saving more, it is good enough.