x = [70, 80, 90, 100, 110]
y = [49.7, 80.6, 122.5, 153.8, 163.0]
f = interpolate.UnivariateSpline(x, y, s=0)
xnew = np.arange(70, 111, 1)
plt.plot(x, y, 'x', xnew, f(xnew))
Interpolation in SciPy: Finding X that produces Y