Source: New York Transit Museum. Note: Inflation adjusted figures are not available before 1913.
Since it was opened in 1904, the New York City subway operated on a flat fare structure, implying that fares are irrespective of the distance traveled. Adjusted to inflation, fares have substantially increased over the years, the 2015 base fare ($2.75) being about three times the fare structure that was prevailing until the 1950s ($0.75 2015 dollars). Still, most users are not paying the full base fare, but get various discounts, namely the monthly unlimited rides plan.
In the history of the New York City subway, 1947 was the lowest year for fare adjusted to inflation, as users paid the equivalent of $0.53 2015 dollars (the fare was 5 cents, the same since the opening of the system in 1904). Then, in the 1950s and 1960s, the fare structure was around $1.25 2015 dollars (15 to 20 cents). Although fares were increased several times in the 1970s and 1980s, these increases only permitted the fare to keep up with the high inflation rates that prevailed around that time. The fare structure remained around $1.75 2015 dollars for that period. From the 1990s, the pattern changed as fare increases systematically surpassed the rate of inflation.