It just means that the user base is increasing at a steady pace. 5-6 years back, the proportion of wallets holding 1 BTC would have been much higher. But many of the large-scale holders would have sold a part of their holdings and majority of the new users could not afford to purchase 1 BTC (the picture is a bit vague, because there are people who hold their coins in exchanges and third parties such as Grayscale). Even this 2% figure surprises me. In the coming years, it will definitely decrease.
We have known for a very long time that this was coming, if you divide all the supply of bitcoin that will ever exist by all the population around the world you get that on average each person will only hold a few mBTC, and this is just a reflection of that, people that have now more than one bitcoin are either people that bought bitcoin when it was cheaper and long term holders or relatively wealthy investors, the time in which a normal person could buy a significant portion of a bitcoin are over and those days will never make a comeback.
If anything things are going in the opposite direction, we should expect that each passing year the amount of bitcoin that each of us holds keeps getting lower, this is why for years in the forum people recommended others to hold their coins no matter what but some people never listen and now they are regretting not following that advice.
