Please note that you wrote to the ResearchGate community, not to the RG team. Note also that none of the platforms, including ResearchGate, is complete. Therefore, no one in the world knows how many papers were published in a given year. (But perhaps there is a rough estimate.) The answer depends also on what types of papers count. See:

https://www.researchgate.net/post/What_counts_as_publication_in_scholarly_journals

https://www.researchgate.net/post/Where_to_find_definitions_on_article_types_and_a_list_of_them