This statistic gives information on the digital buyer penetration worldwide from 2011 to 2018. In 2013, 41.3 percent of global internet users had purchased products online. In 2017, this figure is expected to grow to 46.4 percent.

source from Statista 

Sales organizations are struggling in the new digital world. Approaches that worked for decades are no longer effective. Ironically, the same digital technologies that have upended traditional sales can help forward-thinking companies effectively reinvent their sales management approaches.
With digital buyer penetration, internet users role worldwide in 2018 has increased 50%. However, the e-commerce industry is still set to evolve and expand.
In 2011, the number of digital buyers worldwide reached 792.6 million. More over, the number rose to 903.6 million and forecasters expect there will be 1.32 billion digital buyers across the globe in 2016.
One way of measuring the growth of the e-commerce industry is to analyze the purchase intention rates. Global average; online purchase intention rates of various product categories were calculated in the first quarter of 2011 and it can be compared with purchase intention rates from the first quarter of 2014. The comparison revealed that each product category experienced a growth in purchase intention. In the first quarter of 2014, 34 percent of respondents were planning to purchase an e-book online in the next six months. And, this figure represents a 19 percent growth from 2011. Also, event tickets experienced a 19 percent growth.
Amazon.com and eBay Inc. are two of the world’s largest e-retailers. Their success can be determined by looking at their year-on-year revenue growth from 2006 to 2013. Both companies have experienced fluctuating revenue growth during this time. In 2010, Amazon achieved a 40 percent year-over-year revenue growth, whereas eBay, in the same year only experienced a five percent year-over-year revenue growth.