Banks usually have that many, but some banks run with a tight ship when it comes to coinage and nickels is the one that they usually have the fewest of on-hand, so on a few occasions I went to get a box and came out empty handed. Not worth pushing the bank on it as I would like to continue a good relationship.
Some other food for thought as to why there are more older nickels available.
Halves and dollar coins don't circulate much, so its somewhat clear why older coins are mixed in, but if you think about circulation you will notice that you typically will get at most the following in change:
pennies (4)
quarters (3)
dimes (2)
nickels (1)
Therefore, quarters circulate at a rate of up to 3X that of nickels. Thus, nickels do not touch as many hands. Probably also has an impact into why more silver dimes are found than silver quarters (other than size and how easy they are to spot). Why wheat pennies are still found in the numbers they are, well, my theory is that they just made so many of them. According to my % remaining calculations (see a previous post from near the end of last year I believe). There are around 8% of all wheat pennies minted still in circulation compared to 19% of all pre-1960 nickels (even with only 1.6% of the war nickels).
Back to the original intent of the post.
The fact that any customer should need at most 1 nickel, usually means nobody buys quantities of nickels except us CRHers. I have gotten some weird looks from tellers when buying a box of nickels, while these same tellers don't even blink when I asked for a box of pennies.
HCRH