Do you ever wonder how much money Sony makes alone on its digital sales? Well, here's a good indicator for you.With 2018's year-end data from the three major hardware manufacturers--Sony, Microsoft, Nintendo--now having been divulged over the past few days via financial reports, many have already started comparing the company's earnings to one another. While each publisher did relatively well in its own right, Sony specifically continues to dominate the market in a big way compared to its competition. Need proof? Just look at its digital sales.As pointed out by industry analyst Daniel Ahmad on Twitter, Sony made around $12.5 billion in 2018 purely from PSN. This accounts for digital sales, purchases of add-on content, and other assorted subscription fees like with PS Plus. It's an impressive sum of money in its own right, but even more impressive when compared to the competition.For reference, this digital sales total is larger than the entire sum of what Nintendo made in 2018 both in terms of digital in physical sales. Sony's digital sales also surpass Microsoft's entire earnings for its gaming division in 2018, which as reported a few days ago reached $11.5 billion. So basically, with the rise of digital sales, the returning profitability of annual subscriptions like PS Plus, and the 91+ million PS4s that are in homes around the world, Sony has only had to fall back on its money made from digital purchases to beat the competition. Pretty darn crazy.We've become accustomed in recent years to the sheer insanity of some of these profitability numbers from Sony in the PS4 era, but I'm still always left in shock when I see some of these sales numbers put into context like this. And for the record, Sony made about 20.7 billion in 2018 as a whole when accounting for physical sales as well.Like it or not, the future seems to be going digital and Sony has done a great job of getting its audience more and more used to making transactions in this way the past few years. If Nintendo and Microsoft want to catch up, the best way would likely be to make their digital storefronts that much more alluring.