As a matter of fact, this trend does not seem to have been affected by the bubble bursting at the beginning of 2018, as it shows an increase of 5% from that particular moment.
From January 2017 the growth was as much as 35%, with a peak of 38%. In 2018 growth appeared to be slower, but it accelerated in the first months of 2019, recording an increase of 3% of the addresses containing between 1 and 10 BTCs.
Given the amount held, these are not wallets in the hands of exchanges but almost certainly of private investors who, to date, together own 6 billion dollars in the cryptocurrency.
55% of addresses with exactly 5 BTC had made the purchase before September 2017, while 49% has 10 BTC, indicating that they are long-term hodlers.
The number of operators that hold between 10 and 1000 bitcoins has seen a drop of 10%, while the average investors are increasing, a sign that the interest is increasing, while the interest of institutional operators or large speculators is contracting.