Figure 2
In both graphs, the horizontal axis ranges from 2 to 22 in increments of 2 units. C U S U M: The vertical axis ranges approximately from negative 15 to 15 in increments of 5 units. The legend identifies the two lines: a solid line represents “C U S U M” and a dashed line represents 5 percent significance. The main line begins near 0 at x equals 2, rises to approximately 5 at x equals 9, and then remains relatively stable with small fluctuations between 4 and 5 throughout the remaining years. The upper dashed boundary begins near 4.5 at x equals 2, rises steadily, and reaches approximately 13 at x equals 22. The lower boundary begins near negative 4.5 at x equals 2, slopes downward, and reaches approximately negative 13 by x equals 22. C U S U M of Squares: The vertical axis ranges from negative 0.4 to 1.4 in increments of 0.2 units. The legend identifies the two lines: a solid line represents “C U S U M of Squares” and a dashed line represents 5 percent significance. The main line begins near 0.0 at x equals 2, rises gradually to around 0.4 at x equals 9, continues increasing slowly afterward, and reaches its highest value of approximately 1.0 at x equals 22. The upper dashed boundary begins near 0.33 at x equals 2, rises steadily, and ends close to 1.25 at x equals 22. The lower boundary begins near negative 0.25 at x equals 2, rises gradually, and ends near approximately 0.72 at x equals 22. Note: All numerical values are approximated.CUSUM and CUSUM. Source: Authors' calculations