The asylum rates were issued by the government at the time, by the INS, (what ICE used to be called.), and published in newsletters. In fairness to the INS, however, their examiners had to deal with just about all immigration cases: visas, marriages, etc. They were required to submit asylum applications to the State Department's Bureau of Human Rights and Humanitarian Affairs, and the latter issued what I believe - if I remember correctly - were called "country letters," advising the INS as the the validity of the claim. The INS officials invariably followed the State Dept.'s extremely biased lead. Some of the letters were notoriously, albeit unintentionally, hilarious in how they described conditions in El Salvador and Guatemala. They often were identical, except for the name of the asylum seeker. I saved some of these and showed them to my Canadian counterpart who dealt with asylum claims, and he couldn't believe that a government agency could issue such opinions that flew in the face of overwhelming evidence of tens of thousand of government murders in the two countries. Lawyers who represented these nationalities of asylum seekers said that a few INS examiners told them that they only paid attention to the positive ones, so bad were the State opinions. But they were the main reason for the lousy asylum approval rate for those nationalities, and the higher approval rates for people from leftist countries.
As I noted in a previous post, such was the embarrassing and infamous absurdity of some of the opinions and decisions that the system was reformed when Reagan left and Bush became prez. A new corps of specially trained "asylum officers" was formed to deal with such cases. And in fact, such was the common knowledge of the brutality of the Salvadoran regime and its military, that "temporary protected status" was then granted to all Salvadoran nationals who had arrived by a certain date, as had been granted to countries where there was armed conflict.
Another somewhat disgraceful episode during Reagan's was the US interdiction on the high seas of Haitians trying to leave that country, preventing them from going anywhere and returning them to Haiti, often with no consideration of their asylum claims. Obviously a bridge too far even for Reaganites, the policy was modified to bring them to Guantanamo where they might have their asylum cases considered. I visited them courtesy of the State Department, and who I ran into were not starving migrants, but young healthy men, targets of the Haitian government, one who said through interpreters that he would gladly go back to Haiti if we gave him a rifle to fight its repressive government.