There is no official API or way to get data from Google Play.
Certain websites scrape data from the Google Play website using scripts, but this is not a guaranteed way to get the data.
Google Play's web site patterns often change and scraping data like this is generally a bad idea. Google will likely block most attempts - at least if they're obvious.
As a developer, you have the option of downloading statistics on your own applications, but that's it.
Also... This is hardly a programming question. Seems fairly off topic.