I'd say since 1998. 

1998 Ocarina of Time

2000 Majora's Mask

2001 Oracle of Ages

2001 Oracle of Seasons

2002 The Wind Waker

2003 Ocarina of Time Master Quest

2004 The Minish Cap

2004 Four Swords Adventures

2006 Twilight Princess

2007 Link's Crossbow Training

2007 Phantom Hourglass

2009 Spirit Tracks

Yeah, I remember when Nintendo released a bunch of Zelda titles in a short span of time. Did not like it then and I don't like it now.

Okay, I sold my Wii version of Skyward Sword today (but kept the golden Wiimote+ ), so "Skyward Sword HD Remastered" for Switch can be announced.

Hopefully with several control options.

I don't really get the wish for a Skyward Sword HD. The pointer in the joycon is just not accurate enough. And if they want to tweak the game to work with regular controls, it would pretty much become a different game.

• higher resolution (probably native 1080p docked and native 720p undocked instead of 470p scaled up to 480p) -> much sharper image quality 
• proper anti-aliasing (the Wii version had no anti-aliasing and a lot of ugly jaggies) -> much more stable image quality with less artifacts
• much better textures (with 88 MB RAM and 3 MB GPU texture memory the Wii had very harsh memory limitations) -> much better asset quality
• better lighting effects, water shaders, more complex 3D models, additional environmental animations (f.e. grass physics)... -> a more vivid and immersive Hyrule
• Zelda Skyward Sword on the go instead of limited to TV access

• most actions of Skyward Sword were based mainly on the motion sensors and not on the infrared pointer (the mandatory motion plus didn't enhance the infrared pointer)
• the combination of Joycon sticks for pointing and motion sensor input is probably more accurate than the Wii controls
• many people will favor than different game with optional controls without mandatory motion controls

I tried playing it on an HD tv, it looks REALLY bad. I'd gladly welcome an HD port.

When i first read about this i reacted as if Nintendo wanted to follow other companies' footsteps. Thankfully, that's not necessarily the case.

They could want a Zelda on Switch and mobile devices; they can have 3D, port/remake/remaster games; they can have spin-offs like Hyrule Warriors or even try out other type of action games with only Zelda; RPG games, 2D games (8-16 bits), etc.

Yearly Zelda games can mean a lot of things!

2011 Skyward Sword
2011 Four Swords Anniversary Edition
2011 Ocarina of Time 3D
2013 A Link Between Worlds
2013 Wind Waker HD
2014 Hyrule Warriors
2015 Tri Force Heroes
2015 Majora's Mask 3D
2016 Twilight Princess HD
2016 Hyrule Warriors Legends
2016 Zelda Picross
2017 Breath of the Wild
2018 Hyrule Warriors Definitive Edition

Mess at that post being repeated like 5 times in the thread (not that I disagree with the user cuz Zelda's been a yearly franchise since some time ago).

Yeahh, as already pointed out, they've pretty much managed to make Zelda franchise releases an annual or even bi-annual event already.