Figure 1.
The four line plots are arranged in 2 rows. All x-axes cover 1980 to 2020, labelled at 5-year intervals. The N A R plot has a y-axis from 0 to 20 in increments of 5. N A R begins near 16, peaks near 19 in the early 1980s, and declines to about 6 by the late 1980s. It fluctuates below 10 thereafter, with a rise to nearly 10 around 2008, before declining to about 1 by 2020. The C L T plot has a y axis from minus 10 to 40 in increments of 10. C L T fluctuates markedly throughout the period, ranging from slightly below 0 to above 30. Its highest peak occurs around 2008, above 30, followed by repeated rises and falls before ending below 10 in 2020. The E C I plot has a y axis from 0 to 35 in increments of 5. E C I rises from about 19 to above 30 in the early 1980s, then drops sharply to about 5. It subsequently fluctuates mainly between about 4 and 13 and ends near 9. The A N S plot has a y axis from 5 to 30 in increments of 5. A N S starts near 11, generally rises through the 1980s and 1990s, and reaches about 28 around 2009. It then generally declines and ends near 17 in 2020.Actual series of NAR, CLT, ECI and ANS