diff --git a/README.md b/README.md
index 76f229a2844c874cd666a459fca0db5a50b942d6..efbf28b0832869f2951fd34633cf9a4fbdf77203 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,7 @@ This program uses the following libraries (other versions might work):
 * pandas &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0.24
 * pydub &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0.23
 * pysoundfile &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0.9
+* pytables  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3.6
 * python &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3.6 
 * scipy &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1.2
 
diff --git a/ipi_extract.py b/ipi_extract.py
index d26223907159aed977ae82128adfdb866b5b0019..49b5a064229c788c00b8ce000f1cb38799fac7c2 100644
--- a/ipi_extract.py
+++ b/ipi_extract.py
@@ -735,7 +735,7 @@ def main(args):
     ref_dict['fig'].set_constrained_layout(False)
     plt.show()
     df = pd.DataFrame.from_dict(ref_dict['callback'].df, orient='index')
-    df.to_hdf(outpath, 'df')
+    df.to_hdf(outpath, 'df', format='table')
     return 0