As I am aware, default min SDK set in android studio is 15. I have read that I should increase it as there aren't many (or maybe none) who is still using that android version. Plus, I am planning to use some new features in android studio which only works in higher API.
May I know, as for now what would be your minimum SDK version, so as to guide me choose mine.
The Android Dashboard may answer your question. It contains the most accurate distribution of Android versions with an average delta of 7 days. The current page claims :
Data collected during a 7-day period ending on October 26, 2018.
So you're pretty accurate with this.
To answer your question, based on the dashboard, targeting the API version 19 will cover 96.5% of all current Android devices worldwide
As of October 26, 2018, devices using API level below 16, is quite low(less than 0.5%). Take a look here
In my opinion, if you target API level 16, you get around 99.5% of all devices. Thats the sweet spot between primitive APIs and latest ones. Almost any open source and popular projects still gives support up to API level 16