In the Arthashastra by Chanakya,
The general principles of taxation and the rates of taxation are given in Part 2 Chapter 22 and additional principles for the `replenishment of treasury’ (in times of emergency, war, etc., which may have caused an excessive outflow from the treasury)are given in Part 5 Chapter 2.
Of flowers, fruits, vegetables, roots, bulbous roots, fruits of creepers, seeds, dried fish, and meat, he ( The King) should take one-sixth part(as duty)” [2.22.4].
.”On ksauma, dukula, silk yarn, armours, yellow orpiment, redarsenic, antimony, vermilion, metals of various kinds and ores, on sandalwood, aloe, spices, fermentation, and minor substances, on skins, ivory, bedspreads, coverings and silk cloth, and on products of goats and rams (the duty to be charged is) one-tenth part or one-fifteenth part *
“On clothes, four-footed and two-footed creatures, yarn, cotton, perfumes, medicines, woods, bamboos, barks, leather goods and earthen-ware, and on grains, fats, sugars, salts, wine, cooked food and so on (the duty is) one-twentieth part or one-twenty-fifth part”
In Book 1, Chapter 13 of Arthasastra
, there is a reference to 1/6th as being a general rate.
It is said “Therefore, even forest-dwellers offer the sixth part of their gleaned grains (saying, `This is the share for him who protects us’)” [1.13.9]
Coming Back to here and now.
GST base median is approximately 18 %
In the Chanakya Arthasastra, the base median is approx 16.7 %