bGross national saving is held constant as a share of GDP at 18.
( ( bGross ( national saving ) ) ( ( is ( ( held ( constant ( as ( ( a share ) ( of GDP ) ) ) ) ) ( at 18 ) ) ) . ) )
(ROOT (S (NP (JJ bGross) (JJ national) (NN saving)) (VP (VBZ is) (VP (VBN held) (ADJP (JJ constant) (PP (IN as) (NP (NP (DT a) (NN share)) (PP (IN of) (NP (NNP GDP)))))) (PP (IN at) (NP (CD 18))))) (. .)))
The bGross national saving has a fluctuating share of GDP at 12. 
( ( The ( bGross ( national saving ) ) ) ( ( has ( ( ( a ( fluctuating share ) ) ( of GDP ) ) ( at 12 ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ bGross) (JJ national) (NN saving)) (VP (VBZ has) (NP (NP (DT a) (VBG fluctuating) (NN share)) (PP (IN of) (NP (NNP GDP))) (PP (IN at) (NP (CD 12))))) (. .)))