Sydney racism

Checking my mailbox today after work, I discovered this. This is the first racism mail that I received here in Australia.

"Our economy is in a crisis.
So far, 338,346 immigrants have arrived during it.
This is insane!
Not one more!"

Obviously anonymous.
I tried to find it on google, to see if this number has any significant meaning. No luck.

If you received similar things (or you're the sender), write me! I'm interested to know.