Standard economic indicators-median household income, GDP, unemployment-do not measure the structural composition of personal income: the proportion of total national personal income that flows from ownership rather than labor. This gap leaves policymakers without a standard metric to detect or monitor the gradual structural shift from a labor-income-dominant economy toward a capital-income-dominant one. This paper introduces the Non-Wage Personal Income Ratio (the NWPI Ratio) as a defined, reproducible metric derived directly from publicly available Bureau of Economic Analysis (BEA) National Income and Product Accounts (NIPA) data. The NWPI Ratio is defined as: (Personal Income-Compensation of Employees) ÷ Personal Income, using NIPA Table 2.1, Line 1 and Line 2. Calculated from BEA data, the broad NWPI Ratio rose from 30.2% in 1980 to 39.7% in 2024-a 9.5 percentage point structural shift over 44 years. A narrower ownership-income variant (isolating rental income, personal interest, and personal dividends) rose from approximately 17.9% to 21.0% over the same period. This paper defines the metric, specifies its data sources, presents the historical time series, addresses methodological limitations, and argues for its adoption as a standard indicator in economic opportunity analysis. The NWPI Ratio is introduced as a named term to facilitate entry into policy and academic discourse.