using script to get percentage values and not able to sum upto 100%

Hello All 

I am trying to use a parseFloat() function to convert string to percentage value and then trying to add all of the % values.

but for few scenrios even if the sum is 100%, from the function i get the PctValue either < or > 100.00%

function doing the calculation is as follows -

code -

iterating_through_all_the_fields {

     PctValue += parseFloat(this.getField("Percentage1").valueAsString);

}

sample -

11.12

11.11

11.11

11.11

11.11

11.11

11.11

11.11

11.11

expected sum is 100

but through above mentioned code i get back 99.99

Any help is appreciated in this regard.