Zend certified PHP/Magento developer

Assigning values for a scorecard

I am generating a scorecard with the KPIs being scored from a scale of 1 – 5, 5 being the highest and 1 as the lowest. One of the KPIs is billable hours and I have a dataset from billable hours from last year and Q1 of this year. The mean of the data set is 60 and the standard deviation is 30. I can’t figure out what values to assign between 1 – 5 to ensure a normal distribution in a bell curve. Would appreciate if the excel formula is provided. I’m not very good in statistics and math but I can figure it out with an explanation and samples. Thanks!