NEW YORK ( TheStreet) -- On top of shining a light on investor appetites each month, the fund flow data compiled by the National Stock Exchange also provides evidence of the persistent growth of the ETF universe.Aside from recapturing the $1 trillion mark in October, investors watched the net population of exchange traded funds grow by 14. The breakneck expansion of the ETF universe is impressive, though expected. In their quests to secure market share and survive in the Darwinian environment, both new and veteran ETF sponsors have long sought to provide individuals with unique and attractive ways to gain access to the global marketplace. Today, using ETFs, investors can dice sectors, global markets, and other asset classes into increasingly thinner slices, allowing them tailor their portfolios to meet their personal investment demands. Not all corners of the ETF universe have evolved at the same pace however. On the contrary, in the case of bond ETFs, the growth has been relatively gradual. Whereas investors can turn to a variety of products when attempting to take aim at the domestic bond market, it has traditionally been difficult to gain exposure to international debt. In the past, I have directed investor attention to funds such as the iShares JPMorgan USD Emerging Market Bond Fund ( EMB) and the SPDR S&P International Government Inflation Protected Bond ETF ( WIP). While effective in targeting the debt of popular foreign nations, these funds may leave something to be desired. For example, both funds take aim at foreign debt using broad brush strokes. While investors can use equity-backed products to target individual nations or single sectors within a specific country or region, those looking to expand the reach of their fixed income portfolios beyond the U.S. borders have been forced to take a wide-net approach. The tide, though, appears to be shifting as seen by the recent batch of new fund launches. In September and October, fund companies including Guggenheim, Van Eck, Blackrock, PowerShares, and most recently, PIMCO, have unveiled products that are designed to hone in on the debt of individual nations. In addition to targeting single countries, the bonds underlying new products such as the PowerShares Chinese Yuan Dim Sum Bond Portfolio ( DSUM) and the PIMCO Australia Bond Index Fund ( AUD) are denominated in their local currencies.