average range of data and plot in gnuplot

I have this kind of data:

label-> 1   2   3   4   5val1    1.67E+07    2.20E+07    3.04E+07    7.89E+07    1.24E+08val2    1.71E+07    2.35E+07    2.70E+07    7.80E+07    1.31E+08val3    1.48E+07    2.15E+07    2.74E+07    7.18E+07    1.17E+08val4    1.57E+07    2.07E+07    2.49E+07    7.46E+07    1.27E+08val5    1.32E+07    2.23E+07    3.07E+07    7.50E+07    1.16E+08

I need to plot the label vs the average of each val column, like this:

label-> 1   2   3   4   5val1    1.67E+07    2.20E+07    3.04E+07    7.89E+07    1.24E+08val2    1.71E+07    2.35E+07    2.70E+07    7.80E+07    1.31E+08val3    1.48E+07    2.15E+07    2.74E+07    7.18E+07    1.17E+08val4    1.57E+07    2.07E+07    2.49E+07    7.46E+07    1.27E+08val5    1.32E+07    2.23E+07    3.07E+07    7.50E+07    1.16E+08mean    1.55E+07    2.20E+07    2.81E+07    7.57E+07    1.23E+08

Is there any possibility of perform this operation in gnuplot or should I keep attached to Excel?