A dispiritingly large percentage of phone calls

SPAM

Unwanted messages that flood your inbox or phone, often from unknown senders.

The clue hints at unwanted phone calls, which are often referred to as "spam" just like junk emails. The word "dispiritingly" suggests annoyance, reinforcing the idea of something intrusive and unwelcome. "SPAM" fits because it’s a common term for mass, unsolicited communications, not just in emails but also in calls. The answer plays on the frustration of receiving too many of these bothersome calls.