By contrast, the transition economies have seen, on average, a decline in this ratio, from an already low level of 0.56 in the second half of the 1990s to 0.48 in 2006-2010. While this rough indicator does not take into account possible shifts in the income tax scale or possible variations in the rates of the VAT for different types of goods and services that are consumed in different quantities by the various income groups, it suggests that the evolution of the tax system has become more regressive. Regressive structures of revenue collection make the system dependent on the purchasing power of the lower and middle-income groups, but since this tax base is relatively small, the yield from this source is also limited.