Hello, I have Excel 2007

I have a series of increasing numbers which have been trucated (rounded
down) to integers , eg

2,  2,  2,  3,  3,  3,  3,  4,  5,  5,  6,  6,  6 etc

The decimal part of the numbers has been 'lost' and cannot be recovered.

I want to 'smooth' the data to estimate the original numbers to 1 decimal
place, eg to give someting like

2.0,  2.4,  2.8,  3.1,  3.3,  3.6,  3.9, 4.5,  5.1,  5.7,  6.1,  6.4,  6.8,
...

I am ok at maths and could devise an algorithm to do this, but I wonder if
there is an Excel function which can do it more easily. I have looked at the
functions and cannot see anything obvious, but I might have missed
something.

Any ideas warmly welcomed.

Thanks

K