factor and, through it, the growth capacity of the economy. the other forecasting assumptions do not undergo major changes with respect to the fiscal year of 2017, except for the updating of the quarterly national accounts figures and an explicit modeling of the way in which capital and total factor productivity respond to the immigration - related increase in the labor factor. despite the importance of the labor force increase, its impact on trend growth is not immediate or transmitted one for one. the economy must undergo a process of adjustment while the sharp increase in the supply of labor is completely absorbed, so that new workers are placed in positions that match their skills. the international experience is not conclusive regarding the duration of this transition, because, as i mentioned, the characteristics of the migratory processes have been very different. in any case, it can be expected that as the immigration flow is accommodated, a gradual increase in capital accumulation and productivity will be observed. thus, we estimate that the trend growth of the chilean economy is between 3. 25 % and 3. 75 % for the period 2019 - 2028 ( table 1 ). this estimate compares with the 3. 0 % to 3. 5 % range that we considered before. it is important to note that the use of a range reflects the uncertainty regarding several of the factors that have been mentioned. in particular, this projection considers that the total factor productivity of the non - mining sector will grow 1 % in the next ten years. however, there is uncertainty in light of this variable ’ s volatility of recent years. ii. 4. potential gdp the updating of trend gdp is important for determining the potential gdp of the economy. regarding the latter, we estimate that in the period 2019 - 2021 it will be around 3. 4 % ( around 3. 2 % was the previous estimate ), somewhat below its trend growth ( table 2 ). in this judgment, the initial fall in productivity is combined with page 3 of 18 the increase in the labor force and the expected lags in the adequacy of the capital stock in response to this phenomenon. the updating of potential growth, together with the performance of the economy in the first quarter, drive the activity gap level ( - 0. 7 percentage points ) to be wider than previously considered ( figure 6 ). it is important to note that, with respect to last december, the estimated level of the activity gap is greater in the beginning — the first quarter of 2019 —, but also throughout the projection

of the estimates, i would like to make a couple of precisions regarding the concepts of trend and potential gdp. in the first place, it is evident that estimating the growth capacity of an economy is very important when defining monetary policy and macroeconomic policies in general. in fact, not only the page 2 of 18 central bank estimates trend growth, but also the ministry of finance to calculate the structural income of the treasury. in our case, we estimate two concepts : trend gdp and potential gdp. the first has to do with the medium - term growth capacity of the economy, while the second refers to the level of gdp consistent with stable inflation and, therefore, is adequate to measure the activity gap associated with short - term inflationary pressures. although in the long term the potential and trend growth rates converge to the same number, in the short term there are transitory elements — such as temporary shocks to productivity and restrictions in the use of factors — that alter the productive capacity and cause differences between the two. hence the importance of analyzing them separately ( figure 4 ). ii. 3. trend gdp the updating of our trend growth estimate — which dated back to 2017 — had the purpose of measuring the effects of the considerable immigration flow of recent years on the country's medium - and long - term growth capacity. a box in the report identifies episodes of significant immigration flows into other economies. although each case is, in some sense, unique, and international experiences are not easily transferable, its analysis provides some useful background to understand the chilean case. the first is to confirm the exceptional nature of the chilean experience, due to its size and speed. in addition, given the factors that motivate migration — particularly from venezuela — one can think that it will not be reversed any time soon. secondly, recent immigration is characterized by an average population that is more qualified, younger and with a greater labor participation than the chilean population. third, relative to other countries, chile poses fewer legal impediments to enter the labor market, and unlike other migratory cases, shares the language and other cultural aspects with a majority fraction of the immigrant population. to update our trend growth estimate, we use the population projections for the period 1992 - 2050, published by the national statistics institute ( ine ) at the end of 2018. these reflect the significant immigration flow observed since 2015, which is expected to continue to be important in the coming years ( figure 5 ). this affects the projection of the labor