Why it matters: While there have been concerns over Google Duplex’s potential to eventually replace human workers in certain industries, it seems the technology is still far from that level. Google has revealed that when it comes to the AI booking restaurant appointments, about 25 percent of the calls are made by humans.

When Duplex was shown off at Google’s I/O conference last year there was a lot of controversy over the way it tricked people into thinking it was human when booking reservations—it can even use speech disfluencies such as “umm” and “ah.” This led to the company confirming that the system will identify itself when making calls.

Speaking to the New York Times, Google said its AI assistant isn’t yet smart enough to handle every call it makes. Twenty-five percent of these start with a human in a call center, and 15 percent begin with Duplex but get passed on to a real person.

Google said there are several factors behind why it might use a human instead of the AI to place a call, including whether the business takes reservations, or if the user of the assistant might be a spammer. When the Times tried making bookings with Duplex (via Google Assistant), it found three of the four successful reservations were carried out by humans.

Google added that using the human callers helps generate large quantities of data, which is used to train and improve future versions of Duplex.

Last July, Google was reported to be in talks to incorporate Duplex into the call center industry, but the new report suggests workers don’t have to worry about their jobs just yet.