Commercial solar water heaters began appearing in the United States in the 1890s. These systems saw increasing use until the 1920s but were gradually replaced by cheaper and more reliable heating fuels. As with photovoltaics, solar water heating attracted renewed attention as a result of the oil crises in the 1970s but interest subsided in the 1980s due to falling petroleum prices. Development in the solar water heating sector progressed steadily throughout the 1990s and growth rates have averaged 20% per year since 1999. Although generally underestimated, solar water heating and cooling is by far the most widely deployed solar technology with an estimated capacity of 154 GW as of 2007.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): Why did interest in solar water heating decrease in the 1980s?
Ah, so.. falling petroleum prices

The Super Nintendo Entertainment System (officially abbreviated the Super NES[b] or SNES[c], and commonly shortened to Super Nintendo[d]) is a 16-bit home video game console developed by Nintendo that was released in 1990 in Japan and South Korea, 1991 in North America, 1992 in Europe and Australasia (Oceania), and 1993 in South America. In Japan, the system is called the Super Famicom (Japanese: スーパーファミコン, Hepburn: Sūpā Famikon?, officially adopting the abbreviated name of its predecessor, the Family Computer), or SFC for short. In South Korea, it is known as the Super Comboy (슈퍼 컴보이 Syupeo Keomboi) and was distributed by Hyundai Electronics. Although each version is essentially the same, several forms of regional lockout prevent the different versions from being compatible with one another. It was released in Brazil on September 2, 1992, by Playtronic.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What is another name for the Super Comboy in North America?
Ah, so.. unanswerable

On December 20, 2005, the United States Court of Appeals for the Sixth Circuit ruled in the case of ACLU v. Mercer County that the continued display of the Ten Commandments as part of a larger display on American legal traditions in a Kentucky courthouse was allowed, because the purpose of the display (educating the public on American legal traditions) was secular in nature. In ruling on the Mount Soledad cross controversy on May 3, 2006, however, a federal judge ruled that the cross on public property on Mount Soledad must be removed.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What did a federal judge rule must be removed from private property?
Ah, so..
unanswerable