3分之2 ＝ 2/3 or "two thirds" 20分之6 = 6/20 or "six twentieths" 100分之19 = 19/100 or "nineteen hundredths" or 19% = "nineteen percent" 1000分之35 = 35/1000 or "thirty-five thousandths"

I searched and I found "per mille." But we don't really say "per mille" as much as we say percent. 1/1000 = per mille ------> 35/1000 = Thirty-five per mille I have actually never used this before, but perhaps other countries do.