title: Fix an error in calculating interest in python 3.6
body: <p>I want to calculate interest rate but I am not getting what I supposed to. I should get something like this:</p>
  
  <pre><code>&gt;&gt;&gt; interest_calculator ()
  Enter the following details .
  Your initial amount : 5000
  Number of years : 5
  Annual interest rate ( as a percentage ): 2.35
  Money after 1 year is 5117.5
  Money after 2 year is 5237.76
  Money after 3 year is 5360.85
  Money after 4 year is 5486.83
  Money after 5 year is 5615.77
  Money growth after 5 years is ( as a percentage ) 12.32
  </code></pre>
  
  <p>The code is</p>
  
  <pre><code>def interest_calculator():
      i_amount=eval(input('Your initial amount:'))
      num_yr=eval(input('Number of years:'))
      anual_rate=eval(input('Annual interest rate as percentage:' ))
      money=0
      for i in range(1,num_yr+1): # 1 so that it begins from 1 and not 0
          money= i_amount+ i_amount*(anual_rate/100)*i
          #money=money+money*(anual_rate/100)
  
          print('Money after ',i,'year is',round(money,2))
      print('Money growth after', num_yr,'year is(as percentage',((money-i_amount)/(i_amount))*100)
  </code></pre>