Federal minimum wage in the US in 1956 was $1.00
Silver dollars were still circulating at that time but the US mint was not pressing any new coins because of the oversupply at the mint. The weight of a US silver dollar being passed around in general circulation from those days was 26.73 grams. They were 90% silver making the value of one of those coins worth $24.05 today.
US federal minimum wage today is $7.25
Hence, I can argue that today's minimum wage worker earns ~30% of what an American worker earning the minimum wage in 1956 was earning. Put that in your pipe and smoke it.
Your US$7.25 is NZ$10.39 so just looking at the numbers yours is lower than our min wage at NZ21.20 per hour
The trouble is what one can buy for the same amount
Your Big Macs are more expensive than ours
https://www.statista.com/statistics/274326/big-mac-index-global-prices-for-a-big-mac/