For people interested in empirical work, here are some public and quantitative databases that can potentially help:

• OECD.AI Policy Observatory:  comprehensive databases on various AI policy related data.

• Epoch: comprehensive databases on ML trends.

• AI Tracker: comprehensive database on existing foundational models.

• The State of AI report: various databases on AI trends for the year 2023.

• Think Tank  or Academic Insituttions Reports: Think tank or academic insitutions like CSET or Stanford HAI sometimes publish reports on AI trends with quantitative data.