Maybe one a month. Usually "We saw your profile on GitHub which matches <our vague search criteria> and would you be interested in <hackathon/conference/somesuchthing>?".
To hijack your comment for my own follow-up question. I'm in the EU (Netherlands). Many of these mails are clearly mass E-Mails with just my name as a template sent by some US-based company, they'll include an unsubscribe link for future E-Mails, but aren't unsolicited mass-marketing E-Mails like these illegal in the EU, and if so would it be worthwhile reporting them, and who to?
To hijack your comment for my own follow-up question. I'm in the EU (Netherlands). Many of these mails are clearly mass E-Mails with just my name as a template sent by some US-based company, they'll include an unsubscribe link for future E-Mails, but aren't unsolicited mass-marketing E-Mails like these illegal in the EU, and if so would it be worthwhile reporting them, and who to?