Subject of "found that" ?

Hi~, what do you think the subject of the part underlined "found that~" is?

Finland OR the consequence ? It's confusting to me because there is a comma between "on euqity" and "and then". In this context, both in content and in grammar, please if you have any thoughts, let me know. Thank you~!

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Abolition of streaming or tracking in the 1980s removed differences between subjects studied or levels of difficulty in each subject that had led to pronounced gaps in educational outcomes. An unusually inclusive special education strategy where any child requiring support with an aspect of their learning is provided with special assistance—so that around 50% of students have received special support at some point before the end of high school—also contributes to an unending assault on inequity. The consequence, Sahlberg (2011) has observed often, is that from the 1990s, Finland first improved its performance on equity, and then, as the gaps closed, found that this also led to significant improvements in overall standards or quality.