This chapter comprehensively reviews Bhutan’s aggregate outputs from 1990 to 2022, focusing on expenditure-side GDP and hydropower-led growth. It reconciles multiple versions of the Bhutanese System of National Accounts (BTSNAs) to address inconsistencies and construct reliable long-term series for key indicators such as gross fixed capital formation (GFCF), exports, and imports. A key concern in constructing industry-level productivity accounts is investment, which in Bhutan is closely tied to imports. Ensuring alignment between final demand by product and investment measurement is crucial for accurate productivity analysis. The chapter highlights the significant role of hydropower in driving Bhutan’s nominal GDP growth, accounting for 34.0% of growth from 1990 to 2008 and 22.1% from 2008 to 2022. Bhutan’s high share of investment in GDP, which surpasses that of other South Asian nations and often exceeds China’s, is noteworthy. However, the capital-intensive model raises concerns about resource allocation efficiency and productivity improvements. This chapter lays the groundwork for a deeper understanding of Bhutan’s economic trajectory and future challenges, which will be explored in greater detail in the following chapters.