Same thing happened in the United States -- it is next to impossible
to find any coins from before 1964, because they had all previously
contained silver.

For the sake of precision: that's dimes and higher coins, from
before 1965.

Actually, for some reason they continued to make half-dollars
containing silver (only 40% instead of 90% as before) for another
6 years, and I've seen it claimed that this was a factor in the
almost total disappearance of the coin from circulation about then.
--
Mark Brader | "I was gratified to be able to answer promptly, and I did.
Toronto | I said I didn't know."
| --Mark Twain, "Life on the Mississippi"