The increase reported at the end of the fourth quarter of 2017 is mainly explained by higher spending on final household consumption and higher gross capital formation.
From a report by the Central Bank of Costa Rica:
In the fourth quarter of 2017, economic activity, measured by the trend of the real Gross Domestic Product (GDP), grew at an annualized rate of 3.2%, in response, mainly, to higher spending on final household consumption and in gross capital formation. In the year-on-year comparison, production registered a growth of 3.1%.
For its part, according to the balance of payments, the country presented a current account deficit equivalent to 0.9% of GDP in 2017, which was financed with long-term external savings (direct investment and public sector debt); In addition, the greater availability of currencies that the economy seasonally presents at the end of each year allowed the Central Bank to accumulate reserve assets for USD 264 million.
Economic activity in the fourth quarter increased by 3.2% (annualized quarterly variation), as a result of higher spending on private consumption and gross fixed investment. The final consumption of households grew by 2.6%, this result although positive is lower than the average variation of 2016, which is consistent with the results of the Consumer Confidence Survey and with the behavior of real disposable income and in bank financing directed towards consumer credit.
See full document (in Spanish).
Source (in Spanish): Centralamericandata.com