Earlier today, Google CEO Sundar Pichai announced during his Google I/O keynote that 20 percent of queries on its mobile app and on Android devices are voice searches. He spoke about this in the context of introducing Google’s new Amazon Echo competitor, Google Home.

This 20-percent figure is actually lower than one mentioned by Google Executive Chairman Eric Schmidt in September 2010. At that time, he said “25 percent of Android searches in the US are voice searches.” Regardless of the precise number, it’s clear that voice searches are growing.

In December, we reported on survey data from MindMeld that found that there has been a significant increase in voice assistant and voice search usage, with 60 percent of survey respondents saying that they had started using virtual assistants and voice search in the past 12 months.

The range of virtual assistants, such as Siri, Cortana, Google Voice Search/Now, Viv, Amazon Alexa, and now, Google Home, are collectively training people to search using their voices and to become more “conversational” with search and mobile devices.

As search continues its migration to mobile devices and a larger percentage of those queries are initiated by voice, there are important content and SEO implications. In addition, those queries will become more transactional over time as virtual assistants permit bookings and conversions using voice.

Amazon Alexa, for example, allows users to order a pizza from Domino’s or an Uber ride. Google also announced that it has already integrated a range of third-party transactional services into Google Home, including Uber, Pandora, OpenTable, Spotify, WhatsApp and Ticketmaster.