The chart reflects not only the average monthly salary of Japanese people, but also the cost of both black-and-white and colour TVs during a 20-year period starting in 1953.
Looking at the average salaries first, we can see that in 1953 it was approximately 25,000 Yen. This steadily increased over 10 years to reach about ¥80,000. From then it shot up to reach a massive ¥200,000 by 1973, which is an eightfold increase in total.
Looking now at the prices of TVs, although colour TVs weren’t introduced until 1958, they started at roughly the same cost as black-and-white TVs did in 1953, at a value between ¥150,000 and ¥200,000. Both of them steadily decreased over the time period finishing at ¥90,000 for colour and a little under ¥50,000 for black-and-white.
Overall, then we can clearly see that over these 2 decades salaries went up and the price of both types of TV declined.