[*XMM-Newton*]{}/EPIC\
[@Jiang:2006vn] & – & $-0.20\pm0.04$ & 101 (RL+RQ)& [*XMM-Newton*]{}/EPIC + [*Chandra*]{}/HEG\
[@Jiang:2006vn] & – & $-0.10\pm0.05$ & 75 (RQ) & [*XMM-Newton*]{}/EPIC + [*Chandra*]{}/HEG\
[@Jimenez-Bailon:2005tg] & – & $-0.06\pm0.20$ & 38 (RQ) & [*XMM-Newton*]{}/EPIC\
[@Zhou:2005ys] & – &$-0.19\pm0.04$ & 66 (RQ+RL)& [*XMM-Newton*]{}/EPIC\
[@Page:2004kx] & – &$-0.17\pm0.08$ & 53 (RQ+RL)& [*XMM-Newton*]{}/EPIC\
[@Iwasawa:1993ys] & – &$-0.20\pm0.03$ & 37 (RQ+RL)& [*Ginga*]{}\

\
[@Shu:2012fk] & $1.64\pm0.03^*$ & $-0.11\pm0.03$ & 32 (RQ) & [*Chandra*]{}/HEG\
[@Shu:2010zr] & $1.63\pm 0.04^*$ & $-0.13\pm0.04$ & 33 (RQ+RL) & [*Chandra*]{}/HEG\
\
\

One of the most interesting characteristics of the narrow component of the iron K$\alpha$ line is the inverse correlation between its equivalent width ($EW$) and the X-ray luminosity (e.g., [@Iwasawa:1993ys]). The existence of an anti-correlation between the equivalent width of a line and the luminosity of the AGN continuum was found for the first time in the UV by @Baldwin:1977fk for the CIV$\,\lambda 1549$ line, and was then dubbed the [*Baldwin effect*]{}. A similar trend was later found for several other emission lines such as Ly$\alpha$, \[CIII\]$\,\lambda 1908$, SiIV$\,\lambda 1396$, MgII$\lambda 2798$ [@Dietrich:2002fk], UV iron emission lines [@Green:2001uq], mid-IR lines such as \[ARIII\]$\,\lambda8.99\mu m$, \[SIV\]$\,\lambda10.51\mu m$ and \[NeII\]$\,\lambda12.81\mu m$ [@Honig:2008kx], and forbidden lines as \[OII\]$\,\lambda 3727$ and \[NeV\]$\,\lambda 