please restate you requirements, they are unclear.
does your file look like that below, or its is a single continuous stream unbroken by newline as per your example.
if it looks like the below, does your statement
which column is power, frequency,occurrence ...

....
0.5000 -142 8
0.5000 -143 19
0.5000 -144 14
0.5000 -145 102
0.5000 -146 122
0.5000 -147 106
0.5452 -96 13
0.5452 -97 14
0.5452 -105 3
0.5452 -110 3
.... ....
16.000 -162 87
16.000 -163 115
16.000 -164 151
16.000 -165 77
.....

---------- Post updated at 11:10 AM ---------- Previous update was at 11:05 AM ----------

hmmm

given your request and the following dataset
i would expect

0.5000 -147 122
0.5452 -110 14
16.000 -165 151

not

so, please restate to avoid ambiguity