I believe there were less than 100 people for the whole 2009 and less than 300 for the first half of 2010.
Since this is my first post here on bitcointalk, I would like to take this opportunity to leave my story about Bitcoin
I first heard about bitcoin in a strike of fortune: I was surfing the Web in the Winter of 2009 and got into an uncommon "newspaper-like" website - possibly one of the first mentions about Bitcoin on the Web. I don't remember the exact day but I remember it was during the period just before or after I left my job (2009/02/28). The text was short with about 100~150 words and I remember it started with a title like "A peer-to-peer digital cash system". The text was basically introducing Bitcoin and it ended with a message like "Will Bitcoin be successful? We have to wait and see" - something like this.
Then, I realized the value of 'whatever that thing is' is zero - "no one attributed any value to this 'thing'." "If this is zero, it can't get any lower in the future but only go up. It can eventually 'explode' when people catches on this although not in the near future. It needs time to mature to be successful." - I remember thinking like this.
I remember by then that I Googled and went into bitcoin.org and downloaded the software v0.1.2 or v0.1.3. The website had minimal design by then (it was like a Notepad text) and in order to run the software, the user only needed to do 3 simple steps. The last one was running BITCOIN.EXE.
So, that's what I did. As soon as I ran the application to generate coins, my notebook fan (a 2-year old Sony Vaio) started to 'scream' like I've never seen before. I admit that I have a paranoia when I see EXE files downloaded from unknown sources. Deep in my mind, I associate this type of files from dubious sources with trojan horses. So, what did I do? In the next minute or so, I removed the program from my computer.
Well, my curiosity about Bitcoin did not end on this day. I'm a guy who complains 'everyday' about how the vast majority of us spend a lifetime working to earn money to deposit in banks that use it to invest into something for their own. And the worst thing is they don't take responsibility if they lose our money like they did in 2007 or 2008. So, in the following years, from time to time, I googled 'bitcoin' to know how was bitcoin doing and I was happy to see it growing slowly like a little child. I believed so much in Bitcoin that I even wrote as top priority on my sticky notes on my desktop that I must buy bitcoins. I wrote this note around 2013 and in the beginning of 2016, I received a phone call from my partner who asked me what I was doing. He called me exactly when I was researching about how to buy bitcoins and he replied "What is that? Stop wasting time on silly things. It is time for us to make money!". I don't know why, it somehow convinced me that I had other priorities in the company, so I gave up creating an account on an exchange and I deleted the top priority note. This was the last time I had Bitcoin on my mind...
... Until November 2017... when my colleague from a full-time job that I had to join a year before (because in my company I was not earning regularly and not enough to rent an apartment), said "My friend has been annoying me to buying some coin!" - and my mind immediately associated that coin she was unable to spell correctly to Bitcoin! Oh no! It took me 8 years to finally own a bitcoin, albeit a fraction of it because I jumped into the ship, ferociously, right after that 'Eureka!' in late November 2017. I was furious with myself thinking how is it possible that I took so long to finally have the 'thing' that I have believed since the beginning? The rest of the story, you can already guess: when I saw it reaching almost 20k USD, I diversified my portfolio of less than a bitcoin into altcoins (I never heard of other cryptos until this time) and now I'm losing about 90% of what I've invested.
Moral of the story: the character of an individual determines his destiny. In my case, it was not a matter of believing in Bitcoin; it was a matter of willing to be wealthy and overcoming the fear of having possibly installed a trojan horse in my computer. For our lives to make sense, it is fundamental that we know who we really are and gain conscience of what we are lacking or doing wrong in order to overcome our constrains to achieve our goals in our lifetime.