There are different percentages of orlah fruits on the market each season. According to HaRav Elyashiv זצ"ל, if the total percentage is less than 4%, one can assume it’s not from orlah. Note that the Beis Midrash publicizes the percentage of orlah of the fruits on the market, on a monthly basis. In any case, one needs to separate terumos and maasros from the fruit.
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