The inflation measures the average change in consumer prices, compared to the previous year. It's worth noting that the table in wikipedia references the timeframe from 2013 to 2017 for measuring the inflation.

What kind of nominal interest rate is this? Is it for banks borrowing from the central bank? For what kind of duration (also a year? or is this a 3-Month- or an overnight rate)? It's worth noting that these interest rates are quite recent (mostly from the 2020s) - I wouldn't call this "real" interest rate since the time frames are different.

How does the nominal interest rate of a central bank relate to the single consumer? Why is this a reasonable comparison to begin with?

Also, what's the red line? Is that supposed to mark where both are equal? Why does it miss, e.g. the (256,256) point?