Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
Saab H engine
Table title:
B204 & B234
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Engine </th><th colspan=1 rowspan=1 > Power </th><th colspan=1 rowspan=1 > Torque </th><th colspan=1 rowspan=1 > Compression ratio </th><th colspan=1 rowspan=1 > Bore x Stroke </th><th colspan=1 rowspan=1 > Rod Length </th><th colspan=1 rowspan=1 > Boost pressure </th></tr>
<tr> <td colspan=1 rowspan=1 > B204i: </td><td colspan=1 rowspan=1 > 130 hp (97 kW) @ 5500 rpm </td><td colspan=1 rowspan=1 > 177 N⋅m (131 lb⋅ft) @ 4300 rpm </td><td colspan=1 rowspan=1 > 10.1:1 </td><td colspan=1 rowspan=4 > 90 mm × 78 mm (3.54 in × 3.07 in) </td><td colspan=1 rowspan=4 > 153 mm (6.0 in) </td><td colspan=1 rowspan=1 > NA </td></tr>
<tr> <td colspan=1 rowspan=1 > B204E: </td><td colspan=1 rowspan=1 > 154 hp (115 kW) @ 5500 rpm </td><td colspan=1 rowspan=1 > 219 N⋅m (162 lb⋅ft) @ 3600 rpm </td><td colspan=1 rowspan=3 > 9.2:1 </td><td colspan=1 rowspan=1 > 0.4 bar (5.8 psi) </td></tr>
<tr> <td colspan=1 rowspan=1 > B204L: </td><td colspan=1 rowspan=1 > 185 hp (138 kW) @ 5500 rpm </td><td colspan=1 rowspan=1 > 263 N⋅m (194 lb⋅ft) @ 2100 rpm </td><td colspan=1 rowspan=1 > 0.73 bar (10.6 psi) </td></tr>
<tr> <td colspan=1 rowspan=1 > B204R: </td><td colspan=1 rowspan=1 > 205 hp (153 kW) @ 5500 rpm </td><td colspan=1 rowspan=1 > 280 N⋅m (207 lb⋅ft) @ 2200 rpm </td><td colspan=1 rowspan=1 > 1 bar (15 psi) </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > B234i 1990-1993: </td><td colspan=1 rowspan=1 > 150 hp (112 kW) @ 5500 rpm </td><td colspan=1 rowspan=1 > 212 N⋅m (156 lb⋅ft) @ 3800 rpm </td><td colspan=1 rowspan=1 > 10.1:1 </td><td colspan=1 rowspan=6 > 90 mm × 90 mm (3.54 in × 3.54 in) </td><td colspan=1 rowspan=1 > 147 mm (5.8 in) </td><td colspan=1 rowspan=2 > NA </td></tr>
<tr> <td colspan=1 rowspan=1 > B234i 1994-: </td><td colspan=1 rowspan=1 > 150 hp (112 kW) @ 5600 rpm </td><td colspan=1 rowspan=1 > 210 N⋅m (155 lb⋅ft) @ 4300 rpm </td><td colspan=1 rowspan=1 > 10.5:1 </td><td colspan=1 rowspan=1 > 153 mm (6.0 in) </td></tr>
<tr> <td colspan=1 rowspan=1 > B234E: </td><td colspan=1 rowspan=1 > 170 hp (127 kW) @ 5700 rpm </td><td colspan=1 rowspan=1 > 260 N⋅m (192 lb⋅ft) @ 2100 rpm </td><td colspan=1 rowspan=1 > 9.25:1 </td><td colspan=1 rowspan=4 > 147 mm (5.8 in) </td><td colspan=1 rowspan=1 > 0.55 bar (8.0 psi) </td></tr>
<tr> <td colspan=1 rowspan=1 > B234L: 1990-1993 </td><td colspan=1 rowspan=2 > 200 hp (149 kW) @ 5500 rpm </td><td colspan=1 rowspan=1 > 329 N⋅m (243 lb⋅ft) @ 1900 rpm 5MT </td><td colspan=1 rowspan=1 > 8.5:1 </td><td colspan=1 rowspan=2 > 0.81 bar (11.7 psi) </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > B234L 1994-1998: </td><td colspan=1 rowspan=1 > 323 N⋅m (238 lb⋅ft) @ 1800 rpm 5MT </td><td colspan=1 rowspan=2 > 9.25:1 </td></tr>
<tr> <td colspan=1 rowspan=1 > B234R: </td><td colspan=1 rowspan=1 > 225 hp (168 kW) @ 5500 rpm </td><td colspan=1 rowspan=1 > 342 N⋅m (252 lb⋅ft) @ 1950 rpm </td><td colspan=1 rowspan=1 > 1.08 bar (15.7 psi) </td></tr>
</table>
Question:
How many generations of the B234 engine are there, and what years were each generation made?
Answer:
There are two generations of B234 engine, one made from 1990-1993, the other from 1994 to 1998.