Answer: Prices increased due inflation
Explanation: This is my first answer so bare with me.
It all starts with purchasing power.
But what is purchasing power? Purchasing power is the value of a currency expressed in terms of the number of goods or services that one unit of money can buy. It can weaken over time due to inflation. That's because rising prices effectively decrease the number of goods or services you can buy. Purchasing power is also known as a currency's buying power.
In investment terms, purchasing or buying power is the dollar amount of credit available to a customer based on the existing marginable securities in the customer's brokerage account.
Inflation reduces a currency's purchasing power and what that currency can buy. Loss of purchasing power has the effect of an increase in prices. This basically means pennies were worth more back then than they are now.