Write into google's spreadsheet to round robin phrases based on a counter

[lgarest]

Current behavior
The script puts the selected phrase based on the following criteria:
#day of the year % #phrases
The problem w/ this approach is that when we add phrases, the result calculation deviates the desired selected phrase as seen in this schema:

num	phrase
21	this is row 21
..	..
28	this is row 28

day_of_the_year=273
len(phrases)=35
result=day_of_the_year % len(phrases) # 273 % 35 = 28
output:this is row 28

If we increment by one the phrases:
len(phrases)=36
result=day_of_the_year % len(phrases) # 273 % 36 = 21
output: this is row 21

Desired scenario
• Implement an algorithm to read the phrases and their # of ocurrences
• Pick the phrases w/ lower # of ocurrences
• Pick one randomly from that subgroup