In developed market economies, possession of property used to be a principal factor in income concentration, but its importance has declined. The top 5% of income recipients receive less than one third of their income from property where once the figure was between 50 and 100%. Property income - rent, dividends, profits - in total income had declined to between 10% and 20%, or even less; it was typically above 20% in the 1950s and much higher still in the pre-war period. Private ownership of property still remains concentrated, although the trend has been towards less concentration, due largely to weak equity prices and surge in house prices. At the same time, social ownership of the means of production has increased sharply, mainly through acquisition - often of faltering private enterprises - and sometimes through the establishment of new public industrial, commercial, or non-profit ventures. There has also been a pronounced trend to the separation of management from ownership. Management has become concentrated in fewer institutions, both through business concentration and growth of government. But equally, there has been a trend towards greater regulation over the use of property, both through private action and administrative and judicial regulation. An important effect of the parallel increases in concentration of management or control, and social regulation, has been that governments have been called on more frequently to adjudicate between the different and detailed claims of social groups and interests, and in the process the traditional machinery for decision making in the democratic state has come under severe strain.