U r so welcome.. well, can ur employer mention an average?. I know that there was variation in ur salary, but i think that they maybe able to just mention an approximate average salary.. Cic just wanna make sure that that job is paid job.. i had an extreme difficulty to get the letter from my employer. I spent 2 months only for this letter ☺ . Specially for the salary part. They at first didnot want to provide my salary. But thank GOD they finally after 2 months of fights and stress accepted to provide it to me..
for u situation, if i were u, i would try to:
1. Ask ur employer to mention the average of ur salary in the experience letter. OR
2. If ur employer is not willing to provide the average, then they can mention that ur salary was 40% of the total income.in this case, it is better to add some pay stubs. actualy in my country we donot have annual tax return like here in canada but if u have, it will be great..
Actually in my application i put as much as i can for evidence for everything. If u have anything that u can add to prove ur experience it will be great.
I think CIC may contact foreign workplaces. But not all.i think they might contact foreign employer if they have a doubt about something or wanna to just make sure. in my case i tried to include all documents that can prove my experience. i included reference letter, bank statement from my home country showing the salary deposited every month, my national ID because it has the name of my employer on it. CIC didnot ask me to provide any extra documents. Also my employer didnot inform me that they have been contacted by CIC..
Good luck in ur application