The 1.9% figure you're quoting, is almost universally regarded to be an undercount, aka a lie. At best their actual military spending figures are very fuzzy.
"The Chinese, for example, do not count their research-and-development expenditures, the considerable amount they pay for foreign military purchases, the huge subsidies for their defense industry (which is composed mostly of enterprises owned by the state), or their spending on the Chinese coast guard despite many of their “maritime law enforcement” ships being in effect naval vessels"
In the Foreign Policy article you are quoting: "Although China’s official 2012 defense budget is $106 billion, ...the Pentagon places China’s total military spending at somewhere between $120 and $180 billion."
So we take the number in the middle ($150 billion) and assume it's always a 50% undercut (extremely inaccurate estimate), this will put China's 2016 budget to 1.92%*1.5=2.88%, still lower than Singapore's.
Are you seriously comparing Singapore's relative military spending to China's? There's got to be a point where % mean nothing, and this is definitely it.
Singapore could spend it's whole GDP on the military and China can still wipe it off the face of the Earth :/
So we take the number in the middle ($150 billion) and assume it's always a 50% undercut (extremely inaccurate estimate), this will put China's 2016 budget to 1.92%*1.5=2.88%, still lower than Singapore's.