  In this paper, I present the results on large-scale evolution of density
turbulence of solar wind in the inner heliosphere during 1985 - 2009. At a
given distance from the Sun, the density turbulence is maximum around the
maximum phase of the solar cycle and it reduces to ~70%, near the minimum
phase. However, in the current minimum of solar activity, the level of
turbulence has gradually decreased, starting from the year 2005, to the present
level of ~30%. These results suggest that the source of solar wind changes
globally, with the important implication that the supply of mass and energy
from the Sun to the interplanetary space has significantly reduced in the
present low level of activity.
