Figure 3.
The line chart depicts the annual frequency of Korean railway patent applications based on data from K I P O between 1990 and 2023. The x-axis shows Year of Application from 1990 to 2023, and the y-axis shows Number of Patents. Patent counts start below 50 in the early 1990s, rise steadily through the late 1990s and early 2000s, and increase sharply after 2005. The trend peaks around 2015 at approximately 440 applications, followed by a gradual decline after 2016. From 2018 onward, the number of patents decreases, reaching around 220 by 2023, illustrating long-term growth followed by a recent contraction in patent activity.Frequency of railway patent applications (1990–2023)