I am using pandoc  1.19.1-1 and I am doing a table like this

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Tarea / Meses                                    1   2   3   4   5   6   7   8   9   10   11   12

----------------------------------------------- --- --- --- --- --- --- --- --- --- ---- ---- ----

Descarga de datos MODIS VCF, MODIS Landcover     X   X   X

y otros 

Desarrollo de algoritmos para a generación           X   X   X   X   X

de los parches de bosques mejorados

Análisis de la distribución de parches                               X   X   X   X   

e índices de alerta temprana

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I generate the pdf with the following code 

pandoc test_tbl.md -o test_tbl.pdf -V geometry:vmargin=1in,hmargin=.5in 

In the first column, the result pdf has only one word by line instead of spanning the width of the column, and also the width of the following columns is large so the table does not fit the page. If I eliminate the columns greater than 8 I thought that the table would fit, but columns get wider and again the table doesn't fit the page. I attached both pdf outputs.