Notes. Tracer columns represent the number of sources having a detection reported in that transition. The final column represents the total number of sources presented in each original work, including upper limits and/or nondetections. Upper limits are denoted in square brackets, while nondetections are in parentheses. The original studies from which the line flux densities were extracted are listed in the References column.a: Frayer et al. (1999), Downes et al. (1999), Guilloteau et al. (1999), Frayer et al. (1999), Cox et al. (2002), Downes & Solomon (2003), Genzel et al. (2003), Neri et al. (2003), Sheth et al. (2004), Hainline et al. (2004), Kneib et al. (2005), Greve et al. (2005), Tacconi et al. (2006), b: Borys et al. (2006), Iono et al. (2009), Sturm et al. (2010), Stacey et al. (2010), Hailey-Dunsheath et al. (2012), Bussmann et al. (2013), Geach et al. (2015), Cañameras et al. (2015), Harrington et al. (2016), Khatri & Gaspari (2016), Yang et al. (2017), Díaz-Sánchez et al. (2017), Cañameras et al. (2017a,b), Su et al. (2017), Iglesias-Groth et al. (2017), Amodeo et al. (2018), Cañameras et al. (2018a,b), Geach et al. (2018), Harrington et al. (2018), Dannerbauer et al. (2019), Frye et al. (2019), Nesvadba et al. (2019), Rivera et al. (2019), Harrington et al. (2019), Berman et al. (2022), Kamieneski et al. (2024), c: Veilleux et al. (2013), Spoon et al. (2013), d: Walter et al. (2011), Alaghband-Zadeh et al. (2013), Liu et al. (2015), Kamenetzky et al. (2016b), Bothwell et al. (2017), Yang et al. (2017), Popping et al. (2017), Andreani et al. (2018), Talia et al. (2018), Cañameras et al. (2018b), Harrington et al. (2018), Dannerbauer et al. (2019), Jin et al. (2019), Bourne et al. (2019), Nesvadba et al. (2019), Cortzen et al. (2020), e: Weiß et al. (2013), f: Madden et al. (2013), Herrera-Camus et al. (2018), g: Ouchi et al. (2013), Kanekar et al. (2013), Ota et al. (2014), González-López et al. (2014), Willott et al. (2015), Maiolino et al. (2015), Schaerer et al. (2015), Capak et al. (2015), Inoue et al. (2016), Knudsen et al. (2016), Pentericci et al. (2016), Díaz-Santos et al. (2017), Knudsen et al. (2017), Bradač et al. (2017), Smit et al. (2018), h: References refer to the literature sample with 6 < z < 7 taken from Glazer et al. (2024). Maiolino et al. (2015), Schaerer et al. (2015), Watson et al. (2015), Willott et al. (2015), Inoue et al. (2016), Knudsen et al. (2016), Pentericci et al. (2016), Bradač et al. (2017), Katz et al. (2017), Matthee et al. (2017), Bowler et al. (2018), Hashimoto et al. (2018), Carniani et al. (2018), Smit et al. (2018), Hashimoto et al. (2019), Matthee et al. (2019), Bakx et al. (2020), Carniani et al. (2020), Harikane et al. (2020), Fujimoto et al. (2021), Ferrara et al. (2022), Molyneux et al. (2022), Schouws et al. (2023), Sommovigo et al. (2022), Valentino et al. (2022), Wong et al. (2022), Heintz et al. (2023), Fujimoto et al. (2024), i: Pilbratt et al. (2010), j: Mirabel et al. (1990), Tinney et al. (1990), Young et al. (1995), Casoli et al. (1996), Zhu et al. (1999), Curran et al. (2000), Dunne et al. (2000), Dunne & Eales (2001), Yao et al. (2003), Gao & Solomon (2004a), Thomas et al. (2004), Stevens et al. (2005), Chapman et al. (2005, 2010), Weiß et al. (2005, 2013), Coppin et al. (2006), Hainline et al. (2006), Kovacs et al. (2006), Albrecht et al. (2007), Kuno et al. (2007), Ao et al. (2008), Wilson et al. (2008), Baan et al. (2008), Young et al. (2008), Daddi et al. (2009b), Chung et al. (2009), Wu et al. (2009), Papadopoulos (2010), Carilli et al. (2010, 2011), Engel et al. (2010), Harris et al. (2010), Ivison et al. (2010), Galametz et al. (2011), Koda et al. (2011), Ivison et al. (2011, 2013), Frayer et al. (2010, 2018), Riechers et al. (2011c, 2013, 2020b), Walter et al. (2011, 2012), Cox et al. (2011), Danielson et al. (2011), Lestrade et al. (2011), McKean et al. (2011), Iono et al. (2012), Pappalardo et al. (2012), Schruba et al. (2012), Magnelli et al. (2012), Papadopoulos et al. (2012), García-Burillo et al. (2012), Thomson et al. (2012), Alaghband-Zadeh et al. (2013), Bothwell et al. (2013), Bothwell et al. (2017), Alatalo et al. (2013), Pereira-Santaella et al. (2013), Wong et al. (2013), Bussmann et al. (2013, 2015), Emonts et al. (2013), Sharon et al. (2013, 2016), Cooray et al. (2014), Messias et al. (2014, 2019), Negrello et al. (2014, 2017), Swinbank et al. (2014), Tan et al. (2014), Ueda et al. (2014), Liu et al. (2015), Rosenberg et al. (2015), Cañameras et al. (2015), Dye et al. (2015), Aravena et al. (2016), Scoville et al. (2016), Spilker et al. (2016), Alatalo et al. (2016), Chu et al. (2017), Villanueva et al. (2017), Hughes et al. (2017), Jiao et al. (2017), Huynh et al. (2017), Oteo et al. (2017, 2018), Bolatto et al. (2017), Cao et al. (2017), Popping et al. (2017), Lu et al. (2017), Yamashita et al. (2017), Falgarone et al. (2017), Wong et al. (2017), Yang et al. (2017, 2019), Clark et al. (2018), Béthermin et al. (2018), Enia et al. (2018), Pavesi et al. (2018a,b), Perna et al. (2018), Valentino et al. (2018, 2020), Wang et al. (2018), Dannerbauer et al. (2019), Gómez-Guijarro et al. (2019), Jiao et al. (2019, 2021), Herrero-Illana et al. (2019), Bourne et al. (2019), Hunt et al. (2019), Lapham & Young (2019), Sorai et al. (2019), Jin et al. (2019), Kaasinen et al. (2019), Leung et al. (2019), Nesvadba et al. (2019), Bakx et al. (2020), Boogaard et al. (2020), Michiyama et al. (2020), Izumi et al. (2020), Berta et al. (2021), Ciesla et al. (2020), Drew et al. (2020), Neri et al. (2020), Harrington et al. (2021), Dunne et al. (2021), k: Nayyeri et al. (2016), Bakx et al. (2018), Neri et al. (2020), Cox et al. (2023), Ismail et al. (2023), l: Serjeant et al. (2017), Stach et al. (2018), Hill et al. (2018), Simpson et al. (2019, 2020), Birkin et al. (2021), Chen et al. (2022), Castillo et al. (2023), Liao et al. (2024)