Currently I use USA based VPS. According to Google analytics USA, India, Malaysia, UK are respectively generated majority of my blog traffic.
This is a half empty or half full problem. The majority of your traffic is either mostly your target audience or it's not. You haven't stated if this is your preferred source of traffic. Is this traffic referral, direct or search?
I found a same specification, but low cost VPS provider in Nederland (server also located in NL). I'm interesting to use new provider.
There are many other factors in picking an ISP then simply location. Is this provider any good?
Are there any relationship with hosting country and site SEO?
Yes, but what you want to do know is why is the answer yes.
Google's ranking algorithm takes into account page load times. One of the biggest impacts on load time that a server has no control over is distance. So Google makes the following assumption "if a visitor is physically closer to the server then pages should load faster", but this is relative to where a person performs a search from.
The other factor is the performance of the server itself that hosts your website. If Google's web crawler downloads the pages quickly it remembers that. That gives that page a better ranking over other similar websites that are slower.
So why does Google do this?
While Google is a very large company. They don't have machines doing web crawling in every country. Therefore, when they measure the download times of web pages. They have to adjust those measurements by distance. For websites far from the web crawler it's difficult for them to tell if distance or server performance is the source of delay.
Conclusion
The performance of a VPN will often be slower than the impact of distance. Assuming any respectable ISP is connected to the internet with a respectable connection.
On the Internet there are things I call trunks. These are major pipelines for data. When you perform a traceroute of your website's IP address. You can see what major trunk you are using to access that website.
You want your web server to be as close to a major trunk as possible. This means that data requires the fewest routes from server to trunk. There is nothing you can do about how far a visitor is from their nearest trunk. Some ISPs have horrible internal networks where your server has to pass data through multiple hubs before it gets outside the ISP. Avoid those places.
I found a same specification, but low cost VPS provider in Nederland (server also located in NL). I'm interesting to use new provider.
Oceans do not make for good data trunks, and I don't know anything about the Neverlands. Research who that ISP is connected to.
Update! What if I use cloudflare, then no one can identify the site origin? Am I correct?
The cloud!
You are getting closer to the answer...
What happens in a cloud is that multiple servers work on different parts of the website. For a blog you could split the database and web server to different nodes in the cloud. This is almost the answer you are looking for.
What you want is a content delivery network or CDN.
What happens in a CDN is that your website exists at multiple locations at the sametime. Why is this a good thing? Back to traceroute! You've increased the chances that a visitor will be connected to a server in the CDN via the shortest route.
This is also true for Google's web crawlers. Google will give the blog a relative performance rank based upon the locations of CDN servers. If a CDN has servers in Malaysia then you get a performance tick for Malaysia.
It can be challenging to get a blog running 99% off a CDN. Most people use CDN just for images and video, but if you set it up correctly you can cache your HTML in the CDN.
I do think CloudFlare offers CDN services with their cloud, but the two (cloud and CDN) are not the same.
I know it's all a lot to take in.