How to add Google Analytics per theme?
To add google analytics to every theme,some manual work is required as:-


In your theme's folder ,
select a theme in which you want to add google analytics
open the theme folder and then create a folder for js files
create a js file and include the code provided to you by google for google analytics.
save the file and this way google analytics is installed in your theme.
follow the same procedure for rest all themes.