“…Histograms that show only a single peak and for which the identification in terms of these three categories is not discussed are shown as gray bullets. The data include published work from Cui et al (2001), Xu and Tao (2003), Xu, Xiao, and Tao (2003), Haiss et al (2004, 2009)Chen et al (2006), González et al (2006), He et al (2006), Jang et al (2006), Li et al (2006, 2008), Sek et al (2006), Ulrich et al (2006), Wierzbinski and Slowinski (2006), Huang et al (2007), Nishikawa et al (2007), Park et al (2007), Hihath et al (2008), Huisman et al (2008), Kiguchi, Sekiguchi, and Murakoshi (2008), Xia, Diez-Perez, and Tao (2008), Song et al (2009, 2010)Martin (2010), Arroyo et al (2011), Kim, Hellmuth et al (2011), Kim, Song et al (2011), Rascón-Ramos et al (2015),Su et al (2015), andGil et al (2018). The spread in the data is large, but the systematic trends in the separate works are shown by connecting the data points obtained from three works, namely,Ulrich et al (2006), the H peak from, and the H peak fromHaiss et al (2009).…”