I suspect the parent's statement might be accurate if you invested with another currency. The problem (or uncertainty) is that both the US and Germany left the

I suspect the parent's statement might be accurate if you invested with another currency. The problem (or uncertainty) is that both the US and Germany left the gold-backed systems during those years and the exchange rate between our currencies changed quite a bit during the 1914-1924 period (which is probably why your parent chose that year). If you notice your image's description, it is denominated in 3 different currencies, depending on the years you are looking at.