For best wallets to use, this does not have anything to do with a country rating. The most important thing is to find a good wallet best for you. Blockchain is good, however, there are so many reasons why using an online wallet is not that very good as you do not have control over them. Since you said you only have a phone, blockchain is good, been using it on my android device for years. You can however consider mycellium as I heard it gives some control.
However, I will advise you consider some desktop wallet later on if you do not have the cash to purchase a hardware wallet (they are safer). And if you just want to be storing up and not spending, you may as well just opt for a paper wallet.
This is surely a good option this dude have mentioned here. If you want to thread the saving line and holding for long, paper wallet is not a bad idea since all you need is always your public address to get your funds into your wallet.
It is just very crucial to save it in a very private place since it contains your private key. However, what some other people have mentioned are all good including blockchain for mobile. Just make sure your wallet is backed up and you have your seed.