pre_text: Management Discussion and Analysis Associates "nm" denotes not meaningful. Notes: (1) Based on Singapore Financial Reporting Standards (International). (2) Assuming constant exchange rates for the regional currencies (Indian Rupee, Indonesian Rupiah, Philippine Peso and Thai Baht) from FY 2018. (3) Share of results excluded the Group’s share of the associates’ significant one-off items which have been classified as exceptional items of the Group. (4) Singtel holds an equity interest of 21.0% in Intouch which has an equity interest of 40.5% in AIS. (5) Bharti Telecom Limited (BTL) holds an equity interest of 50.1% in Airtel as at 31 March 2019. In BTL’s standalone books, its loss comprised mainly interest charges on its borrowings.
  (5) Bharti Telecom Limited (BTL) holds an equity interest of 50.1% in Airtel as at 31 March 2019. In BTL’s standalone books, its loss comprised mainly interest charges on its borrowings. (6) Singtel ceased to own units in NetLink Trust following the sale to NetLink NBN Trust in July 2017 but continues to have an interest of 24.8% in NetLink NBN Trust, the holding company of NetLink Trust. The share of results included Singtel’s amortisation of deferred gain of S$20 million (FY 2018: S$32 million) on assets previously transferred to NetLink Trust, but excluded the fair value adjustments recorded by NetLink NBN Trust in respect of its acquisition of units in NetLink Trust. (7) Include the share of results of Singapore Post Limited.
table: Financial Year ended 31 March
table: 2019 2018 Change Change in constant currency (2)
table: (S$ million) (S$ million) (%) (%)
table: Group share of associates' pre-tax proﬁts (3) 1,536 2,461 -37.6 -36.2
table: Share of post-tax proﬁts
table: Telkomsel 843 1,031 -18.3 -12.4
table: AIS 286 292 -1.7 -3.9
table: Globe (3)
table: - ordinary results 251 180 39.3 45.3
table: - exceptional items - 22 nm nm
table: 251 202 23.9 29.1
table: Intouch (3) (4)
table: - operating results 101 106 -4.4 -6.5
table: - amortisation of acquired intangibles (22) (21) 8.3 5.9
table: 79 86 -7.5 -9.5
table: Airtel (3) (131) 101 nm nm
table: BTL (5) (40) (18) 127.8 140.9
table: (171) 83 nm nm
table: Regional associates (3) 1,287 1,694 -24.0 -21.5
table: NetLink NBN Trust/ NetLink Trust (6) 48 72 -32.9 -32.9
table: Other associates (3) (7) 47 57 -17.6 -17.6
table: Group share of associates’ post-tax proﬁts (3) 1,383 1,823 -24.1 -21.8
question: Analyse this data from a financial earnings document. What is the impact of tax on the group share of associates' profits in 2018, in terms of % change?