This isn't too surprising since the coin that appears in poundage accumulates over a period of many years. Coins that are tough to get today will appear in accumulations of this sort. These coins will also tend to be much higher grade than what circulates in the home country. The simple fact it's there at all implies it came over when it was still relatively new.
If you went the the dimes here you'd find a far different assortment. Today the bulk of the dimes are '99 to date. These will account for nearly 75% of them!! The older coins are getting difficult to find at all and when they are they'll be in pretty sorry shape. Besides them all being worn about 35% have serious damage.
When I pull out my poundage and look at the Australian I see mostly older dates in XF/ AU with few after 1980.
Time don't fly, it bounds and leaps.