Panel a: period distribution for TIICs in the Galactic Bulge (OGLE-IV, Soszyński et al. 2017). The two red vertical lines give the period boundaries, according to Soszyński et al. (2011), for the three sub-groups: BLHs (P ≤ 5 days), WVs (5 <  P ≤ 20 days), and RVTs (P > 20 days). The total number of TIICs and the number fractions of the three sub-groups are also labelled. Panel b: same as panel a, but for TIICs in Galactic globular clusters according to Clement et al. (2001), Matsunaga et al. (2006), Pritzl et al. (2003). Panel c: same as panel a, but for TIICs in the Galactic field according to Ripepi et al. (2019). Panel d: same as panel a, but for TIICs in the Large Magellanic Cloud according to Soszyński et al. (2018). Panel e: same as panel a, but for TIICs in the Small Magellanic Cloud according to Soszyński et al. (2018).